DE10008237A1 - Automobile passenger safety restraint control device uses signals from separate acceleration sensors positioned within passenger space and at front of vehicle for rapid response to frontal impact - Google Patents

Abstract

The control device has an acceleration sensor (8) positioned within an automobile passenger space and an acceleration sensor (6,7) mounted at the front of the automobile, for providing respective acceleration signals, with activation of the passenger safety restraint (9) when the integral of the detected acceleration within the passenger space reaches a given threshold value. The latter integral is increased when the signal from the front acceleration sensor indicates a frontal impact.

Description

The present invention relates to a control device for Controlling an occupant protection device of a vehicle, for example an airbag and a seat belt Jig.

A conventional control device for controlling a Occupant protection devices, such as those used in the Japanese publication of a published patent No. 8-85414 has one Accelerometer on a floor tunnel in the Interior of a motor vehicle is provided. The Accelerometer detects an acceleration that is on the vehicle body acts through the floor tunnel, and outputs an analog signal corresponding to the acceleration Control device. The control device integrates this Acceleration signal from the acceleration sensor, detects the occurrence of a collision Operation of an occupant protection device requires on the Based on a comparison between an integrated value of the acceleration signal and a predetermined one Collision decision threshold, and operates that Occupant protection device, for example an airbag.  

If a shock or collision occurs due to a deformation of a Collision part of the vehicle body is added, so it can be assumed that a crash acceleration, which is transferred to the ground tunnel is weakened. Because in this case the acceleration from that on the Acceleration sensor provided in the ground tunnel is detected is small, there is no fear that thereby difficulties in protecting the Inmates evoked at the time of the collision However, there is a fear that there will be a delay until the operation of the occupant protection device becomes. Especially a collision like a staggered one Collision or an oblique collision can lead to one Lead case in which the transferred to the ground tunnel Acceleration is weakened. Accordingly, is under the Viewpoint of improving the control of the occupant Protection device, regardless of whether the Collision acceleration is weakened, which on the in Interior of the vehicle provided acceleration sensor is transmitted, precise control of the occupant Protection device desirable.

An advantage of the present invention is that Provision of an improved control device for a Occupant protection device.

Another advantage of the present invention is the provision of a control device which does exactly that Occupant protection device can control whether or not one Collision acceleration on one Accelerometer is transmitted to the interior of a Vehicle is provided is weakened.  

The foregoing and other advantages are illustrated by a Control device of an occupant protection device achieved which has an interior acceleration sensor which is provided in the interior of a vehicle to a Detect acceleration of the vehicle, and a output corresponding acceleration signal, wherein the following are provided: at least one in front Accelerometer in a front part of the Vehicle is provided to accelerate the vehicle to detect and a corresponding acceleration signal or an integrated value of the acceleration signal as Output sensor output signal; and a control unit that with the interior acceleration sensor and the front Accelerometer is connected to enter the Acceleration signal from the interior acceleration sensor and the sensor output signal of the front Acceleration sensor, wherein the control unit the occupant Protection device starts up when an integrated value of the Acceleration signal of the interior acceleration sensor exceeds a predetermined threshold, the Control unit detects whether the vehicle is on Collision occurs that affects the operation of the occupant Protection device requires, based on the Sensor output signal from the front acceleration sensor, and the integrated value of the interior acceleration sensor increases when the collision is based on the Sensor output signal of the front acceleration sensor is detected.

With such a construction, in addition to detection of a collision based on the interior Accelerometer the fact whether the vehicle is one  Collision occurs based on the Sensor output signal of the front acceleration sensor detected in the front section of the vehicle is provided. If the collision is based on the front acceleration sensor is detected, the integrated value of the acceleration signal of the interior Accelerometer increased. Because the front one Accelerometer in the front of the vehicle is provided, the front acceleration sensor detects a crash acceleration early, and gives that Sensor output signal to the control unit, even in the case a collision like a staggered or oblique Collision, in which a collision acceleration, which is transmitted to the interior acceleration sensor provided in the interior of the vehicle is weakened can be. This allows the integrated value of the interior acceleration sensor is increased, the Control unit exactly the occupant protection device in operation set without a delay in the detection of the Collision is caused.

The above and other advantages will also be by a control device of an occupant protection device achieved which has an interior acceleration sensor which is provided in the interior of a vehicle, for detecting an acceleration of the vehicle and for Output of a corresponding acceleration signal, where there are provided: a first and a second front Accelerometer in the front of the vehicle are provided, both the first and the second front acceleration sensor the acceleration of the Vehicle detected, and a corresponding one Outputs acceleration signal, or an integrated value  the acceleration signal, as a sensor output signal; and a control unit that works with the interior Accelerometer, the first front Accelerometer and the second front Accelerometer is connected to enter the Acceleration signal of the interior acceleration sensor and the sensor output signals of the first and second front acceleration sensor, the control unit Occupant protection device starts up when an integrated Value of the acceleration signal of the interior Acceleration sensor a predetermined threshold exceeds, the control unit detects whether the Vehicle a collision occurs that set in motion of the occupant protection device requires, based on each the sensor output signals of the first and second Accelerometer, the control unit a first Collision time recognizes which one time of the Represents collision based on the Sensor output signal of the first front Acceleration sensor is detected, and a second Collision time recognizes which one time of the Represents collision based on the Sensor output signal of the second front Acceleration sensor is detected, the Control unit a predetermined addition value to the integrated value of the acceleration signal of the interior Accelerometer added when the time difference between the first collision time and the second Collision time is less than the predetermined value.

With such a construction, the first collision time, which represents a time of the collision that based on the first front acceleration sensor  is detected, recognized, and becomes the second Collision time detected, which is a time of Represents collision based on the second front acceleration sensor is detected. If the time difference between the first and second Collision time is less than the predetermined value the integrated value of the interior acceleration sensor elevated. Because the first and the second front Accelerometer in the front section of the vehicle are provided, detect the front Accelerometers crash early, and give the sensor output signals to the control unit, even in In the event of a collision in which a Collision acceleration that affects the interior Accelerometer is transmitted in the interior of the vehicle is provided, can be weakened. As a result, since the integrated value of the interior Accelerometer is immediately raised, the control unit Activate the occupant protection device exactly.

The above and other goals will continue to be achieved achieved a control device of an occupant protection device, which has an interior acceleration sensor which is provided in the interior of a vehicle to a Detect acceleration of the vehicle, and a output corresponding acceleration signal, wherein the following are provided: at least one in front Accelerometer in a front part of the Vehicle is provided for detecting the acceleration of the vehicle and to issue a corresponding Acceleration signal, or an integrated value of the Acceleration signal, as a sensor output signal; and a control unit that works with the interior  Accelerometer and the front accelerometer is connected to input the acceleration signal of the Interior accelerometer and des Sensor output signal of the front acceleration sensor, the control unit thereby adding an value calculates that the integrated value of the Acceleration signal of the front acceleration sensor too an integrated value of the acceleration signal of the Interior accelerometer added, and that Occupant protection device starts up when the added value exceeds a predetermined threshold.

With such a structure, the integrated value of Acceleration signal of the front acceleration sensor and the integrated value of the acceleration signal of the Interior acceleration sensor added. Because the front one Accelerometer in the front section of the vehicle the integrated value of the interior Accelerometer increases immediately, even in the event of a Collision, in which a collision acceleration, which is transmitted to the interior acceleration sensor which is provided in the interior of the vehicle, can be weakened. Therefore, the control unit can be precise put the occupant protection device into operation.

The above and other advantages will also be by a control device of an occupant protection device achieved which has an interior acceleration sensor has provided in an interior of a vehicle is for detecting an acceleration of the vehicle and to output an acceleration signal which the Acceleration represents, whereby the following are provided: at least one front acceleration sensor that in one  front part of the vehicle is provided for detection the acceleration of the vehicle and to output a corresponding acceleration signal; and a Control unit using the interior acceleration sensor and connected to the front acceleration sensor for Entry of the acceleration signals of the interior sensor and of the front acceleration sensor, the control unit an acceleration addition value calculated by Add the acceleration signal of the front Accelerometer to the acceleration signal of the Interior acceleration sensor, and an integrated value of the acceleration addition value, the Control unit puts the occupant protection device into operation when the integrated value of the acceleration addition value is one exceeds a predetermined threshold.

With such a structure Acceleration addition value calculated in that the Acceleration signal from the front acceleration sensor to Acceleration signal from the interior acceleration sensor is added, and the integrated value of the Acceleration addition value calculated. Because the front one Accelerometer in the front part of the vehicle the integrated value of the Acceleration addition value increases immediately, even in the case a collision in which a Collision acceleration that affects the interior Accelerometer is transmitted in the interior of the vehicle is provided, can be weakened. Therefore the control unit can exactly fit the occupant protection device in Put operation into operation.  

Furthermore, the above and other advantages by a control device of an occupant protection device reached, which an interior acceleration sensor has provided in an interior of a vehicle is for detecting an acceleration of the vehicle and to output a corresponding acceleration signal, are provided: at least one front Accelerometer in a front part of the Vehicle is provided for detecting the acceleration of the vehicle and to issue a corresponding Acceleration signal; and a control unit that works with the Interior accelerometer and the front Accelerometer is connected to enter the Acceleration signals from the interior acceleration sensor and the front acceleration sensor, the Control unit an acceleration part above a predetermined value from the acceleration signal of the front acceleration sensor, and one integrated value of the accelerator that calculates Control unit calculates an added value by adding of the integrated value of the acceleration part to one integrated value of the acceleration signal of the interior Acceleration sensor, and the occupant protection device in Operation sets when the added value is a predetermined one Threshold exceeded.

With such a structure, the integrated value of Acceleration part above the predetermined value in the Acceleration signal from the front acceleration sensor to integrated value of the acceleration signal of the interior Accelerometer added. Hence the Integrated value of the interior acceleration sensor immediately increased even in the event of a collision in which  a collision acceleration that is Accelerometer is transmitted in the interior of the vehicle is provided, can be weakened. There the integrated value of the acceleration part above the predetermined value in the acceleration signal of the front acceleration sensor to the integrated value of the Interior acceleration sensor is added, a Difference in size between an integrated value of the front acceleration sensor at the time of a weak Collision and an integrated value of the front Accelerometer at the time of a strong one Collision more clearly. Therefore, you can simply choose between Collision that started the occupant's Protection device required, and a collision distinguished where this is not the case.

The further scope of applicability of the present Invention will become apparent from the detailed below Description even clearer. However, it does noted that while the detailed description and the specific examples preferred embodiments of the Specify the invention, but serve only for explanation, because Specialists in the field after reading this detailed Description of various changes and modifications recognize within the spirit and scope of the invention become.

The invention is illustrated below with reference to drawings illustrated embodiments explained in more detail what other objectives, features and advantages of the invention become clear. It shows:  

Fig. 1 is a block diagram of a first embodiment of the present invention;

FIG. 2 is a circuit diagram of an example for a first and a second front acceleration sensor and for a first and second receiving circuit in FIG. 1;

Figures 3, 4 and 5 are flow charts of a microcomputer in Figure 1;

FIG. 6 is a circuit diagram of another example of the first and second front acceleration sensors in FIG. 1;

. Fig. 7 is a flow chart of the microcomputer of Figure 1 according to a second embodiment of the present invention; . wherein the 7 and 5 together form the flow diagrams for the microcomputer;

. Fig. 8, 9, 10, 11 and 12 are flowcharts of the microcomputer of Figure 1 according to a third embodiment of the present invention;

Fig. 13, 14 flowcharts of the microcomputer 1 of FIG according to a fourth embodiment of the present invention, together with the flow chart of the microcomputer of FIG. 12.;

. Fig. 15, 16 and 17 are flowcharts of the microcomputer of Figure 1 according to a fifth embodiment of the present invention, along with the flowcharts of the microcomputer shown in FIG 8 and FIG. 10.;

. Fig. 18, 19 and 20 are flowcharts of the microcomputer of Figure 1 according to a sixth embodiment of the present invention;

FIG. 21 is an explanatory diagram for explaining collision decision in the sixth embodiment shown in FIG 18, 29 and 20.

FIG. 22 is a flowchart of the microcomputer of FIG. 1 according to a seventh embodiment of the present invention, together with the flowchart of the microcomputer of FIG. 20;

. Fig. 23, 24 flowcharts of the microcomputer of Figure 1 according to an eighth embodiment of the present invention;

Fig. 25, 26 flowcharts of the microcomputer of Figure 1 according to a ninth embodiment of the present invention, together with the flow chart of the microcomputer in accordance with FIG. 20.; and

Fig. 27 is an explanatory diagram for explaining an integration processing of an acceleration signal of a front acceleration sensor in the ninth embodiment shown in FIG. 25, 26 and 20.

In Fig. 1, reference numeral 1 denotes a control unit. The control unit 1 has a microcomputer 2 , a first and a second receiving circuit 3 and 4 , and a driver circuit 5 . Sensor outputs of a first and second front acceleration sensors 5 and 6 are supplied to the microcomputer 2 via the first and second receiving circuits 3 and 4 , a sensor output of an interior acceleration sensor 8 , and the microcomputer outputs a crash detection signal to the driver circuit 5 based on the sensor outputs of the Acceleration sensors 6 to 8 off. When the crash detector signal is supplied, the driver circuit 5 outputs a driver signal to an occupant protection device 9 , and thereby the occupant protection device 9 is put into operation. The occupant protection device 9 is specifically an airbag or a seat belt tensioning device. The control unit 1 is provided on a floor tunnel in the interior of a vehicle.

The first and second front acceleration sensors 6 and 7 are provided on front parts of a vehicle, for example, on the left and right ends of a radiator bracket to which a radiator is attached, so that the first and second front acceleration sensors 6 and 7 have an early acceleration in the event of a crash Can detect collision, for example in an offset collision and an oblique collision. Therefore, for example, the first front acceleration sensor 6 is arranged near a left bumper of the front part of the vehicle, and the second front acceleration sensor 7 is provided near a right bumper of the front part of the vehicle. Since the first and second front acceleration sensors 6 and 7 have a temperature compensation function, as will be explained later, the front acceleration sensors 6 and 7 can be provided regardless of whether they are exposed to the heat from an internal combustion engine. The first and second front acceleration sensors 6 and 7 each have the circuit structure shown in FIG. 2.

FIG. 2 is a circuit diagram showing an example of the front acceleration sensors 6 and 7 and the receiving circuits 3 and 4 of the control unit 1 in FIG. 1.

The first (second) front acceleration sensor 6 ( 7 ) has a piezoelectric element 11 for detecting acceleration, an amplifier circuit having first and second non-inverting amplifier circuits 12 and 13 , and a differential amplifier circuit 14 , a bias resistance circuit 15 , a capacitor 16 , a temperature compensation element 17 as a temperature compensation device, and a reference voltage circuit 18 .

The first, non-inverting amplifier circuit 12 of the amplifier circuit has an operational amplifier 19 of the bipolar transistor type, and a resistor 21 , which is inserted between a negative input terminal and an output terminal of the operational amplifier 29 . The second, non-inverting amplifier circuit 13 of the amplifier circuit has an operational amplifier 20 of the bipolar transistor type, and a resistor 22 , which is inserted between a negative input terminal and an output terminal of the operational amplifier 20 . Operating voltage for the operational amplifiers 19 and 20 is supplied by a sensor voltage supply line 23 . As will be explained later, the control unit 1 supplies a predetermined, constant voltage to the sensor voltage supply line 23 via the receiving circuit 3 ( 4 ). A positive input terminal of the operational amplifier 19 of the first non-inverting amplifier circuit 12 is connected to one end of the piezoelectric element 11 , and a positive input terminal of the operational amplifier 20 of the second non-inverting amplifier circuit 13 is connected to the other end of the piezoelectric element 11 . As a result, output voltages at both ends of the piezoelectric element 11 are amplified without inversion and converted to low impedance by the first and second non-inverting amplifiers 12 and 13, respectively. Since as explained below, the output voltages of the piezoelectric element 11 through the parallel circuit of the capacitor 16 is lowered to the piezoelectric element 11, the resistors 21 and 22 of the first and second non-inverting amplifier circuit 12 and 13 is set to a relatively high value, so that the drop in the output voltages of the piezoelectric element 11 can be compensated for by the gains of the operational amplifiers 19 and 20 .

The differential amplifier circuit 14 of the amplifier circuit has an operational amplifier 24 of the bipolar transistor type. An operating voltage source of the operational amplifier 24 supplies operating voltage via the sensor voltage supply line 23 . A negative input terminal of the operational amplifier 24 is connected via a resistor 25 to the output terminal of the operational amplifier 19 of the first non-inverting amplifier circuit 12 , and is further connected via a resistor 26 to an output terminal of the operational amplifier. A positive input terminal of the operational amplifier 24 is connected via a resistor 27 to the output terminal of the operational amplifier 20 of the second non-inverting amplifier circuit 13 , and receives a reference potential from the reference voltage circuit 18 via a resistor 28 . The differential amplifier circuit 14 performs differential amplification of the output signals of the first and second non-inverting amplifier circuits 12 and 13 , and outputs an acceleration signal as the sensor output signal. As will be explained below, the reference potential from the reference voltage circuit 18 for the differential amplifier circuit 14 is present via a reference voltage buffer amplifier 33 , for matching to the output impedances of the first and second non-inverting amplifier circuits 12 and 13 . As a result, the common mode rejection ratio of the differential amplifier circuit 14 becomes large. The differential amplifier circuit 14 therefore suppresses the influence of an offset voltage as a result of an increase in the gain of the first and second non-inverting amplifier circuits 12 and 13 , respectively.

The bias resistance circuit 5 has a bias resistor 29 which is inserted between the positive input terminal of the first non-inverting amplifier circuit 12 and the reference potential of the reference voltage circuit 18 , and a bias resistor 30 which is inserted between the positive input terminal of the second non-inverting amplifier circuit 13 and the reference potential of the reference voltage circuit 18 is inserted. The capacitor 16 is provided in parallel to the piezoelectric element 11 , so that the total capacitance increases together with the piezoelectric element 11 . This lowers a lower cut-off frequency without increasing the resistance values of the bias resistors 29 and 30 . Since the control unit 1 makes a collision decision by converting acceleration signals from the first and second front acceleration sensors 6 and 7 into speeds, it is necessary to provide an even lower frequency at which changes in speed are more easily detected. For example, it is desirable to provide a frequency even below 10 Hz. Furthermore, if the bias resistors 29 and 30 are set to high resistance values of about 100 MΩ, for example, to lower the lower cutoff frequency, it is not possible to use these resistors in a normal atmosphere. Further, when the bias resistors 29 and 30 are set to the high resistance values described above, a DC voltage can be applied to the piezoelectric element 11 by the influence of a bias current, and this can cause charge migration in the piezoelectric element. Therefore, it is desirable to set the bias resistors 29 and 30 to about 1 MΩ. Since the lower cut-off frequency is determined by the total capacitance of the piezoelectric element 11 and the capacitor 16 and the resistance values of the bias resistors 29 and 30 , the capacitance value of the capacitor 16 is set so that the bias resistors 29 and 30 have a value of 1 MΩ and above In addition, the lower cut-off frequency reaches a low value, for example below 10 Hz. Although the output voltage of the piezoelectric element 11 is reduced by the parallel connection of the capacitor 16 to the piezoelectric element 11 , this is compensated for by the gain increase of the first and second non-inverting amplifier circuits 12 and 13 , as already mentioned above. Since the output temperature characteristic of the piezoelectric element 11 becomes clear through the parallel connection of the capacitor 16 , the temperature compensation element 17 is also provided in order to compensate for the output temperature characteristic of the piezoelectric element 11 . The output temperature characteristic of the piezoelectric element 11 is a positive characteristic. Therefore, the output signal of the piezoelectric element 11 increases as the temperature increases, and decreases as the temperature decreases.

The temperature compensation element 17 is inserted between the negative input terminal of the operational amplifier 19 of the first non-inverting amplifier circuit 12 and the negative input terminal of the operational amplifier 20 of the second non-inverting amplifier circuit 13 . In the present example, the temperature compensation element 17 is a posistor (PTC thermistor). The posistor 17 lowers the gains of the first and second non-inverting amplifier circuits 12 and 13 as the temperature rises, and increases these gains as the temperature drops. As a result, the output signals of the piezoelectric element 11 are compensated for with respect to temperature changes. Since the gains of the first and second non-inverting amplifier circuits 12 and 13 are adjusted by a single temperature compensation element, a reduction in the number of components and a simplification of the circuit structure can be achieved.

The reference voltage circuit 18 has a series connection of voltage dividing resistors 31 and 32 inserted between the sensor voltage supply line 23 and the ground, and the reference voltage buffer amplifier 33 , which consists of a bipolar transistor type operational amplifier. The buffer amplifier 33 receives a voltage divided by the voltage dividing resistors 31 and 32 as a positive input signal, and a negative input terminal is connected to its output terminal. The reference voltage circuit 18 applies the reference potential to the differential amplifier circuit 14 and the bias resistance circuit 15 with the aid of the buffer amplifier 33 . Therefore, matching to the output impedances of the first and second non-inverting amplifier circuits 12 and 13 can be achieved, and thereby the common mode rejection ratio of the differential amplifier circuit 14 is increased. Operating voltage for the reference voltage buffer amplifier 33 is supplied by the sensor voltage supply line 23 . Since the sensor output signals of the first and second front acceleration sensors 6 and 7 are transmitted to the control unit 1 as current changes in the sensor voltage supply line 23 , as will be explained in more detail below, the voltage dividing resistors 31 and 32 are set to relatively high values of a few kΩ, so that the through the. Resistors 31 and 32 current flowing to ground becomes small. In the present example, the reference potential is applied to the bias resistor circuit 15 via the reference voltage buffer amplifier 33 , but it is also possible to directly apply the divided voltage of the resistors 31 and 32 to the bias resistor circuit 15 .

The sensor voltage supply line 23 of the first (second) front acceleration sensor 6 ( 7 ) is connected to the first (second) receiving circuit 3 ( 4 ) of the control unit 1 via a transmission cable 34 , and receives a predetermined constant voltage from a unit voltage supply line 35 in the control unit 1 the first (second) receiving circuit 3 ( 4 ). In the present example, a twisted pair cable is used as the transmission cable 34 from the viewpoint of preventing noise. The output terminal of the operational amplifier 24 of the differential amplifier circuit 14 , which provides the sensor output signal of the front acceleration sensor 6 ( 7 ), is grounded through an output resistor 36 , and thereby the sensor output signal is transmitted as current changes in the sensor voltage supply line 23 of the receiving circuit 3 ( 4 ) the twisted pair cable 34 supplied. Since the operational amplifiers 19 , 20 , 24 and 33 in the front acceleration sensor 6 ( 7 ) operate at almost constant current, the operational current of the operational amplifiers 19 , 20 , 24 and 33 does not affect the sensor output signal which is present as changes in current.

The first (second) receiving circuit 3 ( 4 ) of the control unit 1 has a current mirror circuit 39 , which has a pair of transistors 37 and 38 , and a detector resistor 40 . A transistor 37 of the current mirror circuit 39 is connected at its emitter to the standard voltage supply line 35 , at its collector to the sensor voltage supply line 23 via the twisted-pair cable 34 , and at its base to the collector and a base of the other transistor 38 . The other transistor 38 is connected at its emitter to the standard voltage supply line 35 , and is connected to ground at its collector via the detector resistor 30 . The sensor output signal from the front acceleration sensor 6 ( FIG. 7 ) is supplied as a voltage signal to the microcomputer 2 via the detector resistor 40 .

, Are in the circuit of Fig. 2 when the piezoelectric element 11 detects no acceleration, the differential amplifier circuit 14, a predetermined voltage output from, on the basis of the reference potential of the reference voltage circuit 18, and for this reason, a predetermined current flows through the output resistor 36 to ground. Therefore, a certain current corresponding to the predetermined current flowing through the output resistor 36 of the front acceleration sensor 6 ( FIG. 7 ) is supplied to the unit voltage supply line 37 of the control unit 1 via the sensor voltage supply circuit 23 and the twisted pair cable 34 . In the first (second) receiving circuit 3 ( 4 ), the pair of transistors 37 and 38 supply current to the detector resistor 40 based on the base-emitter voltages corresponding to the determined current flowing through the unit voltage supply line 35 . Therefore, a predetermined voltage signal indicating that no acceleration is detected is supplied to the microcomputer 2 through the detector resistor 40 . In the microcomputer 2 , the predetermined voltage signal is input using an A / D conversion.

On the other hand, when the piezoelectric element 11 detects acceleration, non-inverting amplification is performed on the output voltages of both ends of the piezoelectric element 11 by the first and second non-inverting amplifier circuits 12 and 13 , respectively, and the non-inverted amplified output signals experience differential amplification by the differential amplifier circuit 14 . As a result, the differential amplifier circuit 14 outputs an output voltage that changes in accordance with the detected acceleration, and the output voltage is supplied as a change in current to the unit voltage supply line 35 of the control unit 1 by means of the output resistor 36 . In the receiving circuit 3 ( 4 ), a base-emitter voltage of a transistor 37 of the current mirror circuit 39 varies in accordance with the variations of the current in the standard voltage supply line 35 , that is, in accordance with the sensor output signal of the front acceleration sensor 6 ( 7 ). As a result, the other transistor 38 supplies the detector resistor 40 with a collector current, so that the base-emitter voltage of the other transistor 38 has the same potential as the base-emitter voltage of the one transistor 37 . As a result, the sensor output signal of the front acceleration sensor 6 ( 7 ) is made available as a voltage signal by the detector resistor 40 , and the voltage signal is input into the microcomputer 2 via an A / D conversion. When the detector resistor 40 is set to the same resistance value as the output resistor 36 of the front acceleration sensor 6 ( FIG. 7 ), a voltage is supplied from the detector resistor 40 that is approximately equal to the voltage at both ends of the output resistor 36 .

In the structure shown in FIG. 2, the output fluctuations of the piezoelectric element 11 due to changes in ambient temperature by the gain settings of the first and second non-inverting amplifier circuit compensated by the temperature compensating element 17 12 and 13. Even when the front acceleration sensor 6 (7) is disposed in a place with extreme ambient temperature variations, for example, the direct heat radiation is exposed from the internal combustion engine of the vehicle, thus the sensor output signal does not vary the front acceleration sensor 6 (7) with changes in ambient temperature.

By connecting the capacitor 16 in parallel to the piezoelectric element 11 , the total capacitance is also increased. This allows the lower cutoff frequency to be lowered without increasing the resistance values of the bias resistance values 29 and 30 . Therefore, the front acceleration sensor 6 ( 7 ) can output an even lower frequency, and thereby a sensor output signal can be obtained which facilitates a collision decision. In addition, it is not necessary to set the bias resistors 29 and 30 to such high resistance values that they cannot be used in a common atmosphere. Furthermore, migration in the piezoelectric element 11 that would occur if the bias resistors 29 and 30 were set to high resistance can be prevented.

Furthermore, the sensor output signal of the front acceleration sensor 6 ( 7 ) is transmitted to the receiving circuit 3 ( 4 ) of the control unit 1 as current changes in the voltage supply lines 23 , 34 and 35 . As a result, it is not necessary to provide a signal line. Since it is not necessary to use a ground potential from the vehicle body mass as a reference, more effective noise suppression can take place.

Furthermore, the receiving circuit 3 ( 4 ) of the control unit 1 is provided with the current mirror circuit 39 , which has the transistors 37 and 38 . As a result, a temperature compensation device is required because the temperature characteristics of the base-emitter voltages of the transistors 37 and 38 are balanced. Since the receiving circuit 3 ( 4 ) operates with a voltage supplied to the front acceleration sensor 6 ( 7 ), it is not necessary to generate another operating voltage, and therefore the structure of the receiving circuit 3 ( 4 ) can be extremely simplified.

Referring to FIG. 1, the interior acceleration sensor 8 is provided on the floor tunnel in the vehicle interior, together with the control unit 1. The indoor acceleration sensor 8 detects an acceleration transmitted through the floor tunnel and outputs an acceleration signal to the microcomputer 2 as the sensor output signal. Since the interior acceleration sensor 8 is provided on the floor tunnel in the vehicle interior, in the event of a collision in which a crash acceleration transmitted to the floor tunnel is weakened due to a shock absorption by deformation of the vehicle body, there is a fear that the crash acceleration is small, which is detected by the interior acceleration sensor 8 . In the event of a collision, for example a frontal collision, in which the collision acceleration is easily transmitted to the floor tunnel, the collision acceleration can be detected early by the interior acceleration sensor 8 . A well-known acceleration sensor can be used as the interior acceleration sensor 8 , or an acceleration sensor can be used which is constructed similarly to the front acceleration sensor 6 ( 7 ) in FIG. 2.

The microcomputer 2 of the control unit 1 performs the following controls according to the flowcharts of Figs. 3, 4 and 5, which will be explained below. The microcomputer 2 decides, based on each of the acceleration signals from the first and second front acceleration sensors 6 and 7 , whether the vehicle is experiencing a collision requiring operation of the occupant protection device 9 and increases an integrated value of the interior acceleration signal Acceleration sensor 8 when the collision is detected on the basis of the acceleration signal of the first front acceleration sensor 6 and / or the acceleration signal of the second front acceleration sensor 7 . When the integrated value of the acceleration signal of the indoor acceleration sensor 8 exceeds a predetermined indoor threshold value, the microcomputer 2 outputs the collision detection signal to the driver circuit 5 .

FIGS. 3, 4 and 5 are flowcharts of the microcomputer 2 of FIG. 1. A terminal A of Fig. 4 is connected to a terminal of the same name A of FIG. 3, and terminals B and C of Fig. 5 are connected Terminals with the same designations B and C of Fig. 3 and Fig. 4 connected.

When a supply voltage is applied by turning on an ignition switch (not shown in the drawings) of the vehicle, the microcomputer 2 of the control unit 1 starts the control processing according to the flowcharts, and proceeds to a step 51 after an initialization in a step 50 .

In step 51 , an acceleration signal Gf1 of the first front acceleration sensor 6 is input into the microcomputer 2 , and the microcomputer decides whether the absolute value of the acceleration signal Gf1 is greater than a front reference value Gfo. The front reference value Gfo is a reference value for deciding whether to integrate the acceleration signal Gf1 and an acceleration signal Gf2. As described below, the acceleration signal Gf2 represents the sensor output signal of the second front acceleration sensor 7. The front reference value Gfo is set so that the integration of the acceleration signals Gf1 and Gf2 is not performed when the vehicle is accelerated without crashing due to sudden braking and the like occurs. In step 51 , if the absolute value of the acceleration signal Gf1 is larger than the reference value Gfo, the microcomputer 2 proceeds from step 51 to a step 52 and calculates an integrated value ΔVf1 of the acceleration signal Gf1. In the following step 53 , the microcomputer 2 decides whether the integrated ΔVf1 is greater than a front threshold value ΔVth1. The front threshold value ΔVth1 is a threshold value for deciding whether the vehicle is experiencing a collision requiring the occupant protection device 9 to be started, and is a threshold value related to the integrated ΔVf1 and an integrated value ΔVf2. As will be explained below, the integrated values ΔVf2 are an integrated value of the acceleration signal Gf2 of the second front acceleration sensor 7 . If the integrated value .DELTA.Vf1 is not greater than the threshold value .DELTA.Vth1 in step 53 , the microcomputer 2 proceeds to a step 54 of FIG. 4. If the integrated value ΔVf1 is larger than the threshold value ΔVth1, the microcomputer 2 detects the occurrence of the collision and proceeds to step 55 . In step 55 , a first increment mark P, which was reset to "0" by the initialization in step 50 , is set to "1". The first increment mark P is a mark for setting a factor p of an addition value {(p + q) xC} in step 72 of FIG. 5 to "1" or "0". The factor p is "0" when the mark P is "0", and the factor p is set to "1" when the mark P is set at "1". The microcomputer 2 then begins with step 54 of FIG. 4.

On the other hand, in step 51 , if the absolute value of the acceleration signal Gf1 is not larger than the front reference value Gfo, the microcomputer 2 performs reset processing of steps 56 to 61 , and proceeds to step 54 in FIG. 4 after the reset processing. In step 56 of the reset processing, it is decided whether the integrated value ΔVf1 is "0". If the absolute value of the acceleration signal Gf1 has not already exceeded the front reference value Gfo after the start of control processing, the integrated value ΔVf1 has the initial value, namely "0". Therefore, the microcomputer 2 goes directly from step 56 to step 54 of Fig. 4. If the integrated value ΔVf1 is not "0", the microcomputer 2 proceeds from step 56 to step 57 and decides whether the absolute value of the integrated value ΔVf1 is greater than a front reset reference value ΔVfo. The front reset reference value ΔVfo is a reference value for deciding whether the integrated value ΔVf1 of the first front acceleration sensor 6 and the integrated value ΔVf2 of the second front acceleration sensor 7 should be reset to "0". In the present embodiment, the front reset reference value ΔVfo is set as follows: a <ΔVfo <2a. "a" is a subtraction value, which will be explained below. If the absolute value of the integrated value ΔVf1 is not higher than the reference value ΔVfo, the microcomputer 2 proceeds from step 57 to step 58 , resets the integrated value ΔVf1 to "0", and proceeds to step 54 of Fig. 4. If If the absolute value of the integrated value ΔVf1 is larger than the reference value ΔVfo, the microcomputer 2 proceeds from step 57 to step 59 and decides whether the integrated value ΔVf1 is larger than "0". If the integrated value ΔVf1 is greater than "0", the subtraction value "a" is subtracted from the integrated value ΔVf1 in step 60 . If the integrated value ΔVf1 is not greater than "0", the subtraction value "a" is added to the integrated value ΔVf1 in step 61 . The microcomputer 2 then proceeds to step 54 of FIG. 4. Since the acceleration signals Gf1 and Gf2 of the first and front acceleration sensors 6 and 7 fluctuate as a result of resonance phenomena and the like, the acceleration signals Gf1 and Gf2 can temporarily become smaller than the front reference value Gfo, after becoming larger than the Gfo value while a crash acceleration is detected. In such a case, in the present embodiment, a previously integrated value is not immediately reset to "0", but is gradually returned in the direction of the reset direction using the subtraction value "a". As a result, when the acceleration signals Gf1 and Gf2 again exceed the front reference value Gfo, the integration processing can be continued from the previously integrated value, and thereby a collision detection can be quickly performed. The integrated value ΔVf1 becomes smaller than "0" in step 59 if, for example, a collision occurs in the vehicle from behind. In such a case, since the integrated value ΔVf1 takes a negative value, the first increment flag P is not set. Further, in such a case, an integrated value is processed toward the reset direction by step 61 , and thereby an unstable signal is prevented from continuing.

In step 54 of FIG. 4, the acceleration signal Gf2 of the second front acceleration sensor 7 is input to the microcomputer 2 , and the microcomputer decides whether the absolute value of the acceleration signal Gf2 is larger than the front reference value Gfo. In step 54 , if the absolute value of the acceleration signal Gf2 is larger than the reference value Gfo, the microcomputer 2 proceeds to step 62 and calculates the integrated value ΔVf2 of the acceleration signal Gf2. In the following step 63 , the microcomputer 2 decides whether the integrated value ΔVf2 is greater than the front threshold value ΔVth1. If the integrated value ΔVf2 is not larger than the threshold value ΔVth1, the microcomputer 2 proceeds from step 63 to step 64 of FIG. 5. If the integrated value ΔVf2 is larger than the threshold value ΔVth1, the microcomputer 2 detects the occurrence of a collision and proceeds to step 65 . In step 65 , a second increment mark Q, which was reset to "0" by the initialization in step 50 , is set to "1". The second increment mark Q is a mark for setting a factor q of the addition value {(p + q) × C} in step 72 of FIG. 5 to "1" or "0". The factor q is "0" when the mark Q is "0", and the factor q is set to "1" when the mark Q is set to "1". The microcomputer 2 then proceeds to step 64 of FIG. 5.

On the other hand, in step 54 , if the absolute value of the acceleration signal Gf2 is not larger than the front reference value Gfo, the microcomputer 2 goes into a reset processing of steps 66 to 71 and proceeds to step 64 of FIG. 5 after the reset processing. In the reset processing of steps 66 to 71 , the same processing is performed as the above-described reset processing of steps 56 to 61 with respect to the first front acceleration sensor 6 . It is therefore decided in step 66 whether the integrated value ΔVf2 is "0". If the integrated value ΔVf2 is "0", the microcomputer 2 goes directly from step 66 to step 64 of FIG. 5. If the integrated value ΔVf2 is not "0", the microcomputer 2 proceeds from step 66 to step 67 . In step 67 , a decision is made as to whether the absolute value of the integrated value ΔVf2 is greater than the front reset reference value ΔVfo. If the absolute value of the integrated value ΔVf2 is not greater than the reference value ΔVfo, the microcomputer 2 returns the integrated ΔVf2 to "0" in step 68 and then proceeds to step 64 of FIG. 5. If the absolute value of the integrated value ΔVf2 is larger than the reference value ΔVfo, the microcomputer 2 proceeds from step 67 to step 69 and decides whether the integrated value ΔVf2 is larger than "0". If the integrated value ΔVf2 is greater than "0", the subtraction value "a" is subtracted from the integrated value ΔVf2 in step 70 from 85213 00070 552 001000280000000200012000285918510200040 0002010008237 00004 85094n. If the integrated value ΔVf2 is not greater than "0", the subtraction value "a" is added to the integrated value ΔVf2 in step 71 . The microcomputer 2 then proceeds to step 64 of FIG. 5. In such a case where the vehicle collides from behind, the second increment mark Q is not set because the integrated value ΔVf2 becomes negative. An integrated value in such a case is processed by the step 71 toward the reset direction.

In step 64 of FIG. 5, an acceleration signal Gt of the interior acceleration sensor 8 is input to the microcomputer 2 , and the microcomputer decides whether the absolute value of the acceleration signal Gt is larger than an interior reference value Gto. The interior reference value Gto is a reference value for deciding whether the acceleration signal Gt should be integrated. The interior reference value Gto is set so that integration of the acceleration signal Gt is not performed during acceleration without collision of the vehicle, which occurs due to sudden braking and the like. In step 64 , if the absolute value of the acceleration signal Gt is larger than the reference value Gto, the microcomputer 2 proceeds to step 72 and calculates an integrated value ΔVt by adding the addition value {(p + q) × C} to an integrated value of the acceleration signal Gt. In the addition value {(p + q) × C}, C is a numerical constant. If neither the first increment mark P nor the second increment mark Q is set, the addition value {(p + q) × C} is "0". If either the mark P or the mark Q is set, the addition value {(p + q) × C} is "C". If both marks P and Q are set, the addition value {(p + q) × C} is "2C". Therefore, the integrated value ΔVt is increased to {the integrated value of the acceleration signal Gt + C} when either the mark P or the mark Q is set, and is further increased to {the integrated value of the acceleration signal Gt + 2C} when both are set are. After step 72, the microcomputer proceeds to step 73 and decides whether the integrated value ΔVt is greater than the interior threshold value ΔVth2. The interior threshold ΔVth2 is a threshold for deciding whether the vehicle is in a collision requiring the occupant protection device 9 to be operated. The indoor threshold value ΔVth2 and the above-mentioned front threshold value ΔVth1 are set on the basis of tests, namely on the basis of a collision which requires the occupant protection device 9 to be put into operation and a collision in which the starting is not required. In step 73 , if the integrated value .DELTA.Vt is not greater than the threshold value .DELTA.Vth2, the microcomputer 2 returns to step 51 of FIG. 3. The microcomputer 2 runs through the flowcharts of FIGS . 3, 4 and 5 within a very short time. Therefore, even if a collision is taking place, the integrated value ΔVt sometimes does not exceed the threshold value ΔVth2 in step 73 , for example due to the duration of the integration of the acceleration signal Gt. In such a case, the microcomputer 2 returns to step 51 of Fig. 3 and becomes the one described above. Tax processing repeated. In step 73 , if the integrated value .DELTA.Vt is larger than the threshold value .DELTA.Vth2, the microcomputer 2 proceeds to a step 74 , outputs the crash detection signal to the driver circuit 5 , and ends the control processing. The driver circuit 5 , when the collision detection signal is supplied from the microcomputer 2 , outputs the driver signal to the occupant protection device 9 , and thereby the occupant protection device 9 such as an air bag is put into operation.

On the other hand, in step 64 , if the absolute value of the acceleration signal Gt is not larger than the indoor reference value Gto, the microcomputer 2 proceeds to reset processing of steps 75 to 80 , and returns to step 51 of FIG. 3 after the reset processing. In the reset processing of steps 75 to 80 , the same processing as the above-described reset processing of steps 56 to 61 is performed with respect to the first front acceleration sensor 6 . It is therefore decided in step 75 whether the integrated value ΔVt is "0". If the integrated value ΔVt is "0", the microcomputer 2 returns directly to step 51 of FIG. 3. If the integrated value ΔVt is not "0", the microcomputer 2 proceeds to step 76 . In step 76 , it is decided whether the absolute value of the integrated value ΔVt is larger than an interior reset reference value ΔVto. If the absolute value of the integrated value ΔVt is not larger than the reference value ΔVto, the microcomputer 2 resets the integrated value ΔVt to "0" in step 77 , and then returns to step 51 of FIG. 3. If the absolute value of the integrated value ΔVt is larger than the reference value ΔVto, the microcomputer 2 proceeds from step 76 to step 78 . The interior reset reference value ΔVto is a reference value for deciding whether the integrated value ΔVt of the interior acceleration sensor 8 should be reset to "0", and is set in accordance with the above-described front reset reference value ΔVfo. In step 78 , a decision is made as to whether the integrated value ΔVt is greater than "0". If the integrated value ΔVt is greater than "0", the subtraction value "a" is subtracted from the integrated value ΔVt in step 79 . If the integrated value ΔVt is not greater than "0", the subtraction value "a" is added to the integrated value ΔVt in step 80 . The microcomputer 2 then returns to step 51 of FIG. 3. If the vehicle crashes from behind, the integrated value of the acceleration signal Gt takes a negative value, and the marks P and Q are not set as mentioned above. Therefore, the crash detection signal is not provided to the driver circuit 5 . Furthermore, an integrated value of the acceleration signal Gt in this case is processed in the direction of the reset direction by step 80 .

According to the first embodiment described above, the first and second increment marks P and Q are set on the basis of the sensor output signal of the first and second acceleration sensors 6 and 7, respectively. When either the mark P or the mark Q is set, the integrated value ΔVt of the interior acceleration sensor 8 is increased to {the integrated value of the acceleration signal Gt + C}. If both marks P and Q are set, the integrated value ΔVt is further increased to {the integrated value of the acceleration signal Gt + 2C}. Then, when the integrated value ΔVt exceeds the interior threshold value ΔVth2, the occupant protection device 9 is started. As mentioned above, the first and second front acceleration sensors 6 and 7 are provided on the right and left sides of the front part of the vehicle, respectively. Even in the event of a collision as an oblique or offset collision in which the collision acceleration, which on the interior of the acceleration sensor 8 is transmitted, is provided on the floor tunnel, can be weakened, therefore, the first and / or second front acceleration sensor 6 or 7 detect the collision acceleration early and output the sensor signal to the control unit 1 . As a result, since the integrated value .DELTA.Vt is increased directly by setting the mark P and / or the mark Q, the control unit 1 can exactly set the occupant protection device 9 in motion without causing a delay in the collision decision.

The sensitivity of the first and second front acceleration sensors 6 and 7 can be changed simply by changing the front threshold value ΔVth1. Therefore, the sensitivity setting is easy according to vehicle types and the like, and moreover, a spread of sensitivity can be reduced.

FIG. 6 is a circuit diagram showing another example of the first and second front acceleration sensors of FIG. 1. In Fig. 6, the same components as in Fig. 2 are denoted by the same reference numerals.

In Fig. 6, reference numeral 6 '( 7 ') denotes a first (second) front acceleration sensor. The front acceleration sensor 6 '( 7 ') is used in the construction according to FIG. 1 instead of the first (second) front acceleration sensor 6 ( 7 ) from FIG. 2. In the front acceleration sensor 6 '( 7 ') an amplifier circuit has a first and a second, non-inverting amplifier circuit 80 or 81 with integration function and a differential amplifier circuit 82 with integration function. As a result, the front acceleration sensor 6 '( 7 ') outputs an integrated value of an acceleration signal as a sensor output signal. The first and second non-inverting amplifier circuits 80 and 81 have capacitors 83 and 84 , respectively, which are connected in parallel to the resistors 21 and 22 , in addition to the construction of the first and second non-inverting amplifier circuits 12 and 13 of FIG. 2. The differential amplifier circuit 82 has capacitors 85 and 86 which are respectively connected in parallel to the resistors 26 and 28 , in addition to the construction of the differential amplifier circuit 14 of Fig. 2. With such a construction, the integrated value of the acceleration signal as the sensor output signal from the front acceleration sensor 6 '( 7 ') is supplied to the microcomputer 2 of FIG. 1. In this example, the structure and operation of other sections are the same as described with reference to FIG. 2.

Fig. 7 is a flow chart 1 of the microcomputer 2 of Fig. According to a second embodiment. Fig. 7 shows the flowchart in the case where the first and second front acceleration sensors 6 'and 7 ' of Fig. 6 are used, respectively, and the microcomputer 2 operates in accordance with this flowchart instead of the flowcharts of Fig. 3 and 4. Terminals B and C of FIG. 7 are connected to terminals of the same designation B and C of FIG. 5. FIG. 7 therefore forms the flowcharts of the microcomputer 2 together with FIG. 5.

When the control processing is started, the microcomputer 2 of the control unit 1 proceeds to step 98 after an initialization according to step 97 . In step 98 , an integrated acceleration signal ΔVf1 is supplied to the microcomputer 2 from the first front acceleration sensor 6 ', and the microcomputer decides whether the integrated value ΔVf1 is larger than the front threshold value ΔVth1. If the integrated value .DELTA.Vf1 is greater than the threshold value .DELTA.Vth1, the microcomputer 2 sets the first increment mark P to "1" and proceeds to a step 100 . If the integrated value ΔVf1 is not greater than the threshold value ΔVth1, the microcomputer 2 proceeds directly to step 100 . In step 100 , an integrated value ΔVf2 of an acceleration signal from the second front acceleration sensor 7 ′ is input into the microcomputer 2 , and the microcomputer decides whether the integrated value ΔVf2 is greater than the threshold value ΔVth1. If the integrated value .DELTA.Vf2 is greater than the threshold value .DELTA.Vth1, the microcomputer 2 sets the second increment flag Q to "1" and proceeds to step 64 of FIG. 5. If the integrated value ΔVf1 is not greater than the threshold value ΔVth1, the microcomputer 2 proceeds directly to step 64 in FIG. 5.

In the processing of FIG. 5, as described above, the integrated value ΔVt of the indoor acceleration sensor 8 is increased to {the integrated value of the acceleration signal Gt + C} when either the mark P or the mark Q is set, and is the integrated value ΔVt further increased to {the integrated value of the acceleration signal Gt + 2C} when both marks P and Q are set. Then, when the integrated value ΔVt exceeds the indoor threshold value ΔVth2, the occupant protection device 9 is started.

In the second embodiment described above, since the microcomputer 2 does not have to perform integration and reset processing with respect to the sensor output signals of the first and second front acceleration sensors 6 'and 7 ', respectively, the structure can be simplified and the processing speed can be improved.

Although the first and second non-inverting amplifier circuits 80 and 81 and the differential amplifier circuit 82 each have the integration function in the example of FIG. 6, the first or the second non-inverting amplifier circuits 80 and 81 or the differential amplifier circuit 82 can also be used have the integration function.

Two front acceleration sensors are used in the first and second embodiment used, however, is intended this does not limit the scope of the invention become. The number of front acceleration sensors can be one, or more than two. If only a front one Accelerometer is used, it is desirable that the front accelerometer in a central part a vehicle front is provided where a shock when Collision can be easily intercepted, for example near a cooler or near the center of one Radiator bracket, which holds a radiator. There a such part in a vehicle body relatively soft a shock can simply be absorbed in the collision and will usually be the transfer of a Acceleration of collision on the floor tunnel of the vehicle weakened. If the front accelerometer in one such part is provided, so in the case of a Collision, in which the transfer of the Collision acceleration on the ground tunnel weakened during a central mast collision, in which a central part of a vehicle front side with collides with a mast, for example one Lighting mast, and in an underride collision, at which one front of the vehicle under the rear  Section of a truck and the like, the collision acceleration can be detected early. Of course you can. the front accelerometer, which is attached as described above, to everyone of the embodiments of the present invention become.

The factors p and q are set to "1" by Setting the first and second increment mark P and Q in the first and second embodiments, however the factors p and q can be optimal as required Values can be set.

Figs. 8, 9, 10, 11 and 12 are flowcharts of the microcomputer 2 of FIG. 1 according to a third embodiment. Figs. 8 to 12 are used in the micro computer 2 instead of the flowcharts of FIGS. 3 to 5. Terminals F and G of Fig. 9 are connected to terminals having the same designations F and G in Fig. 8, a terminal D of Fig. 10 is connected to a terminal with the same designation D of Fig. 8, terminals I and J of FIG. 11 are connected to terminals with the same designations I and J of FIG. 10, and terminals H and E of FIG. 12 are connected to terminals with the same designations H and E of FIG. 8 and FIG. 10.

When the control processing is started, the microcomputer 2 of the control unit 1 proceeds to a step 111 after initialization according to a step 110 . In step 111 , a timer t is increased by +1. Then the microcomputer 2 proceeds to a step 112 , an acceleration signal Gf1 of the first front acceleration sensor 6 is supplied to it, and the microcomputer decides whether an absolute value of the acceleration signal Gf1 is greater than the front reference value Gfo. If the absolute value of the acceleration signal Gf1 is larger than the reference value Gfo, the microcomputer 2 proceeds from step 112 to a step 113 and calculates an integrated value ΔVf1 of the acceleration signal Gf1. In a subsequent step 114 , the microcomputer 2 decides whether the integrated value ΔVf1 is greater than the front threshold value ΔVth1. If the integrated value ΔVf1 is not greater than the threshold value ΔVth1, the microcomputer 2 proceeds to step 115 of FIG. 10. If the integrated value .DELTA.Vf1 is greater than the threshold value .DELTA.Vth1, the microcomputer 2 detects the occurrence of a collision and proceeds to step 116 of FIG. 9. The front reference value Gfo and the front threshold value ΔVth1 are the same as described in the first embodiment shown in FIGS . 3 to 5.

In step 116 of FIG. 9, a first increment flag P, which was reset to "0" by the initialization of step 110 , is set to "1". The first increment mark P is a mark for setting a factor p of an addition value {(p + q + r) × C} in step 145 of FIG. 12 to "1" or "0". The factor p is "0" when the label P is "0", and the factor p is set to "1" when the label P is set to "1". After step 116, the microcomputer 2 proceeds to a step 117 and decides whether a first decision mark Ftp is "1". The first decision mark Ftp is a mark for deciding whether the integrated value ΔVf1 exceeds the front threshold value ΔVth1 for the first time after the start of control processing. The flag Ftp is reset to "0" when step 110 is initialized, and is set to "1" in a step 119 which will be explained below. If the mark Ftp is not "1" in step 117 , the mark Ftp indicates that the integrated value ΔVf1 exceeds the threshold value ΔVth1 for the first time. In this case, the microcomputer 2 recognizes a first collision time Tp based on the timer t in a step 118 , sets the flag Ftp to "1" in the following step 119 , and proceeds to a step 120 . The first collision time Tp indicates a time at which the collision is detected on the basis of the sensor output signal of the first front acceleration sensor 6 . If the flag Ftp is set to "1" in step 119 , the microcomputer 2 proceeds directly from step 117 to step 120 without going through steps 118 and 119 the next time. In step 120 , the microcomputer 2 decides whether a second increment mark Q, which will be explained below, is "1". If the mark Q is not equal to "1", the microcomputer 2 goes directly from step 120 to step 115 of FIG. 10. If the mark Q is "1", the microcomputer 2 proceeds to a subsequent step 121 and decides whether a time difference Tq-Tp between a second collision time Tq to be explained below and the first collision time Tp is less than a predetermined value To. If the time difference Tq-Tp is not less than the predetermined value To, the microcomputer 2 proceeds directly from step 121 to step 115 of FIG. 10. If the time difference Tq-Tp is less than the predetermined value To, the microcomputer 2 detects the occurrence of a high-impact collision, such as a high-speed collision, in which the occupant protection device 9 needs to be quickly operated, and goes on a step 122 over. In step 122 , a third increment mark R, which was reset to "0" by the initialization of step 110 , is set to "1". The third increment mark R is a mark for setting a factor r of an addition value {(p + q + r) × C} in step 145 of FIG. 12 to "1" or "0". The factor r is "0" when the label R is "0", and the factor r is set to "1" when the label R is set to "1". The microcomputer 2 then proceeds to step 115 of FIG. 10.

If the absolute value of the acceleration signal Gf1 of the first front acceleration sensor 6 is not greater than the front reference value Gfo in step 112 of FIG. 8, the microcomputer 2 goes to a reset processing of. Steps 123 through 128 , and returns to step 115 of FIG. 10 after the reset processing. In the reset processing of steps 123 to 128 , the same processing is carried out as the above-described reset processing according to steps 56 to 61 in FIG. 3.

In step 115 of FIG. 10, an acceleration signal Gf2 of the second front acceleration sensor 7 is input to the microcomputer 2 , and the microcomputer decides whether an absolute value of the acceleration signal Gf2 is larger than the front reference value Gfo. If the absolute value of the acceleration signal Gf1 is larger than the reference value Gfo, the microcomputer 2 proceeds to step 115 to a step 129 and calculates an integrated value ΔVf2 of the acceleration signal Gf1. In a subsequent step 130 , the microcomputer 2 decides whether the integrated value ΔVf2 is greater than the front threshold value ΔVth1. If the integrated value ΔVf2 is not greater than the threshold value ΔVth1, the microcomputer 2 proceeds to a step 131 in FIG. 12. If the integrated value ΔVf2 is larger than the threshold value ΔVth1, the microcomputer 2 detects the occurrence of the collision and proceeds to step 132 of FIG. 11.

In step 132 of FIG. 11, the second increment flag Q, which was reset to "0" by initializing step 110 , is set to "1". The second increment flag Q is a flag for setting a factor q of the addition value {(p + q + r) × C} in step 145 of FIG. 12 to "1" or "0". The factor q is "0" when the mark Q is "0", and the factor q is set to "1" when the mark Q is set to "1". The microcomputer proceeds to step 133 after step 132 and decides whether a second decision flag Ftq is "1". The second decision mark Ft1 is a mark for deciding whether the integrated value ΔVf2 exceeds the front threshold value ΔVth1 for the first time after the start of control processing. The flag Ftq is reset to "0" at the initialization of step 110 , and is set to "1" in a step 135 which will be explained below. If the mark Ftq is not "1" in step 133 , the mark Ftp indicates that the integrated value ΔVf1 exceeds the threshold value ΔVth1 for the first time. In this case, the microcomputer 2 detects a second collision time Tq based on the timer t in a step 134 , sets the flag Ftq to "1" in the following step 135 , and proceeds to a step 136 . The second collision time Tq indicates a time at which the collision is detected based on the sensor output signal of the second front acceleration sensor 7 . If the flag Ftq is set to "1" in step 135 , the microcomputer 2 proceeds directly from step 133 to step 136 without going through steps 134 and 135 the next time. In step 136 , the microcomputer 2 decides whether the first increment mark P is "1". If the mark P is not "1", the microcomputer 2 goes directly from step 136 to step 131 of FIG. 12. If the flag P is "1", the microcomputer 2 proceeds to a subsequent step 137 and decides whether a time difference Tp-Tq between the first collision time Tp and the second collision time Tq is less than the predetermined value To. If the time difference Tp-Tq is not less than the predetermined value To, the microcomputer 2 proceeds directly from step 137 to step 131 of FIG. 12. If the time difference Tp-Tq is less than the predetermined value To, the microcomputer 2 detects the occurrence of a high impact collision, such as a high speed collision, in which the occupant protection device 9 needs to be quickly operated, and goes to a step 138 about. In step 138 , the third increment mark R is set to "1". The microcomputer 2 then proceeds to step 131 of FIG. 12.

In step 115 of FIG. 10, if the absolute value of the acceleration signal Gf2 of the second front acceleration sensor 7 is not larger than the front reference value Gfo, the microcomputer 2 goes to reset processing of steps 139 to 144 , and goes to step 131 of FIG. 12 after reset processing via. In the reset processing of steps 139 to 144 , the same processing is carried out as the above-described reset processing of steps 66 to 71 in FIG. 4.

In step 131 of FIG. 12, an acceleration signal Gt of the interior acceleration sensor 8 is supplied to the microcomputer 2 , and the microcomputer decides whether the absolute value of the acceleration signal Gt is greater than the interior reference value Gto. If the absolute value of the acceleration signal Gt is larger than the reference value Gto, the microcomputer 2 proceeds to step 145 and calculates an integrated value ΔVt by adding the addition value {(p + q + r) × C} to an integrated value of the acceleration signal Gt. With the addition value {(p + q + r) × C}, C is a numerical constant. It is clear from FIGS. 9 and 11 that only when both the first and the second increment mark P and Q are set and, moreover, the time difference between the first and second collision times Tp and Tq is smaller than the predetermined value To , the third increment mark R is set to "1". Therefore, the addition value {(p + q + r) × C} is "0" when neither the P nor the Q mark is set. If either the mark P or the mark Q is set, the addition value {(p + q + r) × C} is "C". If the marks P and Q are set, the addition value {(p + q + r) × C} is "2C". If the marks P, Q and R are set, the addition value {(p + q + r) × C} is "3C". Therefore, the integrated value ΔVt is increased to {the integrated value of the acceleration signal Gt + C} when either the mark P or the mark Q is set, is further increased to {the integrated value of the acceleration signal Gt + 2C} when the mark P and Q are set, and is further increased to {the integrated value of the acceleration signal Gt + 3C} when the marks P, Q and R are set. The microcomputer 2 proceeds to step 146 after step 145 and decides whether the integrated value ΔVt is larger than the interior threshold value ΔVth2. If the integrated value ΔVt is not greater than the threshold value ΔVth2, the microcomputer 2 returns to step 111 in FIG. 8. If the integrated value .DELTA.Vt is larger than the threshold value .DELTA.Vth2, the microcomputer 2 proceeds to step 147 , outputs the crash detection signal to the driver circuit 5 , and ends the control processing. The driver circuit 5 , when the collision detection signal is supplied from the microcomputer 2 , outputs the driver signal to the occupant protection device 9 , and thereby the occupant protection device 9 is put into operation. The interior reference value Gto and the interior threshold value ΔVth2 are the same as was described in the first embodiment of FIGS. 3 to 5.

On the other hand, in step 131, if the absolute value of the acceleration signal Gt of the indoor acceleration sensor 8 is not larger than the indoor reference value Gto, the microcomputer 2 proceeds to reset processing of steps 148 to 153 , and returns to step 111 of Fig. 8 after the reset processing back. In the reset processing of steps 148 to 153 , the same processing as the above-described reset processing of steps 75 to 80 in FIG. 5 is performed.

In the third embodiment described above, in addition to increasing the integrated value ΔVt of the interior acceleration sensor 8 based on the sensor output signals of the first and second front acceleration sensors 6 and 7 , as described in connection with the first embodiment, the integrated value ΔVt is further increased if the time difference between the first and second collision times Tp and Tq is smaller than the predetermined value To. The first collision time Tp is a time of the collision that is detected based on the sensor output of the first front acceleration sensor 6 , and the second collision time Tq is a time of the collision that is detected based on the sensor output of the second front acceleration sensor 7 . In the event of a collision with a high impact load, for example in a high-speed collision, the time difference between the first and second collision times Tp and Tq is small. Therefore, even in the event of a collision such as a high-speed collision, it is possible to precisely put the occupant protection device 9 into operation without causing a delay in the collision decision.

FIGS. 13 and 14 show flowcharts of the microcomputer 2 of FIG. 1 according to a fourth embodiment. FIGS. 13 and 14 are flow charts in that case is, in which the first and second front acceleration sensor 6 'or 7' of Fig. 6 are inserted, and are used for the operation of the microcomputer 2 instead of the flowcharts of FIGS. 8, 9, 10 and 11. A terminal E in FIG. 13 is connected to a terminal with the same designation E from FIG. 12, and terminals K and H from FIG. 14 are connected with terminals with the same designation K and H from FIG. 12 and Fig. 13 connected. Therefore, FIGS . 13 and 14 together with FIG. 12 form the flowcharts for the microcomputer 2 .

At the start of the control processing, the microcomputer 2 of the control unit 1 proceeds to a step 161 after an initialization in a step 160 . In step 161 , a timer (software timer) t is incremented by +1. The microcomputer 2 then proceeds to a step 162 , is supplied with an integrated value ΔVf1 of an acceleration signal from the first front acceleration sensor 6 ', and the microcomputer decides whether the integrated value ΔVf1 is greater than the front threshold value ΔVth1. If the integrated value ΔVf1 is not greater than the threshold value ΔVth1, the microcomputer 2 proceeds to a step 163 in FIG. 14. If the integrated value ΔVf1 is larger than the threshold value ΔVth1, the microcomputer 2 detects the occurrence of a collision and proceeds to step 164 . In steps 164 to 170 , the same processing is carried out as in the above steps 116 to 122 in Fig. 9. Therefore, in step 164, the first increment flag P is set to "1". In a subsequent step 165 , a decision is made as to whether the first decision mark Ftp is "1". If the flag Ftp is not "1", the microcomputer 2 recognizes the first collision time Tp in a step 166 , sets the flag Ftp to "1" in a step 167 , and then proceeds to a step 168 . When the Ftp flag is set to "1", the microcomputer 2 goes directly from step 165 to step 168 . In step 168 , it is decided whether the second increment mark Q is "1". The microcomputer 2 proceeds to step 163 of Fig. 14 if the mark Q is not "1", and proceeds to a subsequent step 169 if the mark Q is "1". In step 169 , a decision is made as to whether the time difference Tq-Tp between the first collision time Tp and the second collision time Tq is smaller than the predetermined value To. If the time difference Tq-Tp is not less than the predetermined value To, the microcomputer 2 proceeds to step 163 of FIG. 14. If the time difference Tq-Tp is less than the predetermined value To, the microcomputer 2 sets the third increment flag R to "1" in a step 170 , and then proceeds to step 163 of FIG. 14.

In step 163 of FIG. 14, an integrated ΔVf2 of an acceleration signal is supplied to the microcomputer 2 from the second front acceleration sensor 7 ', and the microcomputer decides whether the integrated value ΔVf1 is greater than the front threshold value ΔVth1. If the integrated value ΔVf1 is not larger than the threshold value ΔVth1, the microcomputer 2 proceeds to step 131 of FIG. 12. If the integrated value ΔVf1 is larger than the threshold value ΔVth1, the microcomputer 2 detects the occurrence of the collision and proceeds to step 171 . In steps 171 to 177 , the same processing is carried out as in steps 132 to 138 in Fig. 11 described above . Therefore, in step 171, the second increment flag Q is set to "1". In a subsequent step 172 , it is decided whether the decision mark Ftq is "1". If the flag Ftq is not "1", the microcomputer 2 recognizes the second collision time Tq in a step 173 , sets the flag Ftq to "1" in a step 174 , and then proceeds to a step 175 . If the flag Ftp is "1", the microcomputer 2 goes directly to step 175 . In step 174 , it is decided whether the first increment mark P is "1". The microcomputer 2 proceeds to step 131 of FIG. 12 if the mark P is not "1", and proceeds to a subsequent step 176 if the mark P is "1". In step 176 , it is decided whether the time difference Tp-Tq between the first collision time Tp and the second collision time Tq is smaller than the predetermined value To. The microcomputer 2 proceeds to step 131 of Fig. 12 when the time difference Tp-Tq is not less than the predetermined value To. If the time difference Tp-Tq is less than the predetermined value To, the microcomputer 2 sets the third increment flag R to "1" in a step 177 , and proceeds to step 131 of FIG. 12.

In the fourth embodiment described above, since the microcomputer 2 did not have to perform integration and reset processing with respect to the sensor output signals of the first and second front acceleration sensors 6 'and 7 ', respectively, the structure can be simplified and the processing speed can be improved.

The factors p, q and r thereby become "1" set that the first, second and third, respectively Increment mark P, Q and R at the third and fourth Embodiment is set, but the Factors p, q and r can also be set to free as required Set selectable values.

The Fig. 15, 16 and 17 show flowcharts of the microcomputer 2 of FIG. 1 according to a fifth embodiment. The flowcharts of FIGS . 15 to 17 are used in the microcomputer 2 instead of the flowcharts of FIGS . 9, 11 and 12. Terminals F and G of Fig. 15 are connected to terminals with the same designation F and G of Fig. 8, terminals I and J of Fig. 16 are connected to terminals with the same designation I and J of Fig. 10, and terminals H and E of FIG. 17 are connected to terminals with the same designation H and E of FIG. 8 in FIG. 10. Therefore, FIGS. 15 to 17 together with FIGS . 8 and 10 form the flowcharts of the microcomputer 2 .

If the integrated value ΔVf1 of the acceleration signal Gf1 of the first front acceleration sensor 6 is greater than the front threshold value ΔVth1, the microcomputer 2 of the control unit 1 proceeds to a step 180 of FIG. 15 and decides whether the first decision mark Ftp is "1" is. The Ftp brand is as described in FIG. 9. If the flag Ftp is not equal to "1", namely if the integrated value ΔVf1 exceeds the threshold value ΔVth1 for the first time after the start of control processing, the microcomputer 2 proceeds to a step 181 and recognizes the first collision time Tp from the timer (software The timer of step 111 of Fig. 8. Then, in a step 182, the microcomputer 2 sets the flag Ftp to "1", and proceeds to a step 183 . If the mark Ftp is "1" in step 180 , the microcomputer 2 goes directly from step 180 to step 183 without going through steps 181 and 182 . In step 183 , the microcomputer 2 decides whether the second decision flag Ftq is "1". The brand Ftq is as described in Fig. 11. If the mark Ftq is not equal to "1" because the second collision time Tq based on the second front acceleration sensor 7 has not yet been recognized, the microcomputer 2 proceeds directly from step 183 to step 115 of FIG. 10. If the flag Ftq is "1", the microcomputer 2 proceeds to a subsequent step 184 and decides whether a time difference Tq-Tp between the second collision time Tq and the first collision time Tp is less than a predetermined value Ts. The microcomputer 2 goes directly from step 184 to step 115 of FIG. 10 if the time difference Tq-Tp is not less than the predetermined value Ts, and proceeds to step 185 if the time difference Tq-Tp is less than the predetermined value Ts . In step 185 , an increment mark S, which was reset to "0" by the initialization in step 110 of FIG. 8, is set to "1". The increment mark 5 is a mark for setting a factor s of an addition value (s × C) in step 193 of FIG. 17 to "1" or "0". The factor s is "0" when the label S is "0", and the factor s is set to "1" when the label S is set to "1". After step 185 , the microcomputer 2 proceeds to step 115 of FIG. 10.

If the integrated value ΔVf2 of the acceleration signal Gf2 of the second front acceleration sensor 7 is greater than the front threshold value ΔVth1 in step 130 of FIG. 10, the microcomputer 2 proceeds to step 186 of FIG. 16 and decides whether the second decision mark Ftq is equal Is "1". If the flag Ftq is not equal to "1", namely when the integrated value ΔVf2 exceeds the threshold value ΔVth1 for the first time after the start of control processing, the microcomputer 2 proceeds to a step 187 and recognizes the second collision time Tq from the timer (software timer ) t of step 111 of FIG. 8. Then, the microcomputer 2 sets the flag Ftq to "1" in a step 188 and proceeds to a step 189 . If the flag Ftq is set to "1" in step 188 , the microcomputer 2 proceeds directly from step 186 to step 189 without going through steps 187 and 188 . In step 189 , the microcomputer 2 decides whether the first decision mark Ftp is "1". If the mark Ftp is not equal to "1", since the first collision time Tp based on the first front acceleration sensor 6 has not yet been recognized, the microcomputer 2 goes directly from step 189 to a step 192 of FIG. 17. If the flag Ftp is "1", the microcomputer 2 proceeds to a subsequent step 190 and decides whether a time difference Tp-Tq between the first collision time Tp and the second collision time Tq is less than the predetermined value Ts. The microcomputer 2 17 proceeds directly from step 190 to step 192 of FIG. 17 if the time difference Tp-Tq is not less than the predetermined value Ts, and proceeds to step 191 if the time difference Tp-Tq is less than the predetermined value Ts In step 191 , the increment mark S is set to "1".

In step 192 of FIG. 17, the microcomputer 2 is supplied with an acceleration signal Gt from the indoor acceleration sensor 8 , and the microcomputer decides whether the absolute value of the acceleration signal Gt is larger than the indoor reference value Gto. If the absolute value of the acceleration signal Gt is larger than the reference value Gto, the microcomputer 2 proceeds to a step 193 and calculates an integrated value ΔVt by adding the addition value (s × C) to an integrated value of the acceleration signal Gt. In the addition value (s × C), C is a numerical constant. If the increment mark S is not set to "1", the addition value (sx × C) is "0". If the mark S is set to "1", the addition value (s × C) is equal to "C". Thereby, when the flag S is set, namely, when the time difference between the first collision time Tp based on the first front acceleration sensor 6 and the second collision time Tq based on the second front acceleration sensor 7 is smaller than the predetermined value Ts, the integrated one Value ΔVt increases to {the integrated value of the acceleration signal Gt + C}. After step 193, the microcomputer 2 proceeds to a step 194 and decides whether the integrated value ΔVt is greater than the interior threshold value ΔVth2. If the integrated value ΔVt is not greater than the threshold value ΔVth2, the microcomputer 2 returns to step 111 in FIG. 8. If the integrated value .DELTA.Vt is larger than the threshold value .DELTA.Vth2, the microcomputer 2 proceeds to step 195 , outputs the crash detection signal to the driver circuit 5 , and ends the control processing.

On the other hand, in step 192, if the absolute value of the acceleration signal Gt of the indoor acceleration sensor 8 is not larger than the indoor reference value Gto, the microcomputer 2 proceeds to reset processing according to steps 196 to 201 , and returns to step 111 of Fig. 8 after the reset processing . In the reset processing of steps 196 to 201 , the same processing as the above-described reset processing of steps 75 to 80 in FIG. 5 is performed.

In the fifth embodiment described above, when the time difference between the first and second collision times Tp and Tq is smaller than the predetermined value Ts, the integrated value of the acceleration signal Gt of the interior acceleration sensor 8 is increased. The first collision time Tp is a time of the collision that is detected based on the sensor output of the first front acceleration sensor 6 , and the second collision time Tq is a time of the collision that is detected based on the sensor output of the second front acceleration sensor 7 . If the integrated value ΔVt, namely {the integrated value of the acceleration signal Gt + s × C} is greater than the interior threshold value ΔVth2, the occupant protection device 9 is put into operation. The first and second front acceleration sensors 6 and 7 are provided on the right and left sides of the front part of the vehicle. Therefore, even in the event of a collision, such as an oblique or offset collision, wherein the collision acceleration, which is transmitted to the indoor acceleration sensor 8, which is provided on the floor tunnel, can be mitigated, the first and second front acceleration sensor 6, or 7 detect the collision acceleration early and supply the sensor output signal to the control unit 1 . As a result, since the integrated value .DELTA.Vt is increased directly by setting the mark S, the control unit 1 can put the occupant protection device 9 into operation without causing a delay in the collision decision.

Although in the fifth embodiment, the factor s by Setting the increment mark S to "1" the factor s can be set to one as required selectable value.

The Fig. 18, 19 and 20 show flowcharts of the microcomputer 2 of FIG. 1 according to a sixth embodiment. The flow charts of FIGS . 18 to 20 are used in the microcomputer 2 instead of the flow charts of FIGS . 3 to 5. A terminal L of Fig. 19 is connected to a terminal having the same designation L of Fig. 18, and terminals M and N of Fig. 20 are connected to terminals having the same designation M and N of Figs. 18 and 19.

When control processing starts, the microcomputer 2 proceeds to a step 211 after an initialization in a step 210 . In step 211 , an acceleration signal Gf1 of the first front acceleration sensor 6 is supplied to the microcomputer 2 , and the microcomputer decides whether an absolute value of the acceleration signal Gf1 is greater than the front reference value Gfo. If the absolute value of the acceleration signal Gf1 is larger than the reference value Gfo, the microcomputer 2 calculates an integrated value ΔVf1 of the acceleration signal Gf1 in a step 212 , and proceeds to a step 219 of FIG. 19. The front reference value Gfo is the same as in the first embodiment.

On the other hand, in step 211 , if the absolute value of the acceleration signal Gf1 is less than the front reference value Gfo, the microcomputer 2 goes to reset processing of steps 213 to 218 , and after the reset processing goes to step 219 of FIG. 19. In the reset processing of steps 213 to 218 , the same processing is carried out as in the above-described reset processing of steps 56 to 61 in FIG. 3.

In step 219 of FIG. 19, an acceleration signal Gf2 of the second front acceleration sensor 7 is supplied to the microcomputer 2 , and the microcomputer decides whether an absolute value of the acceleration signal Gf2 is greater than the front reference value Gfo. If the absolute value of the acceleration signal Gf2 is larger than the reference value Gfo, the microcomputer 2 calculates an integrated value ΔVf2 of the acceleration signal Gf2 in a step 220 , and proceeds to a step 227 of FIG. 20.

On the other hand, in step 219 , when the absolute value of the acceleration signal Gf2 is less than the front reference value Gfo, the microcomputer 2 goes to reset processing of the. Steps 221 through 226 and, after the reset processing, proceeds to step 227 of FIG. 20. In the reset processing of steps 221 to 226 , the same processing is carried out as in the above-described reset processing of steps 66 to 71 in FIG. 4.

In step 227 of FIG. 20, an acceleration signal Gt of the interior acceleration sensor 8 is supplied to the microcomputer 2 , and the microcomputer decides whether an absolute value of the acceleration signal Gt is greater than the interior reference value Gto. If the absolute value of the acceleration signal Gt is larger than the reference value Gto, the microcomputer 2 calculates an integrated value ΔVt of the acceleration signal Gt in step 228 and proceeds to the following step 229 . In step 229 , the microcomputer 2 calculates a first added value ΔVt + ΔVf1 by adding the integrated value ΔVf1 of the first front acceleration sensor 6 to the integrated value ΔVt of the interior acceleration sensor 8 , and decides whether the first added value ΔVt-ΔVf1 is greater than one predetermined threshold Vth. The threshold value Vth is set on the basis of test results, namely on the basis of a collision which requires the occupant protection device 9 to be put into operation and a collision which does not require this. In step 229 , if the first added value ΔVt + ΔVf1 is less than the threshold value Vth, the microcomputer 2 proceeds to a subsequent step 230 , calculates a second added value ΔVt + ΔVf2 by adding the integrated value ΔVf2 of the second front acceleration sensor 7 to integrated value ΔVt of the interior acceleration sensor 8 , and decides whether the second added value ΔVt + ΔVf2 is greater than the threshold value Vth. If the second added value ΔVt + ΔVf2 is smaller than the threshold value Vth in step 230 , the microcomputer 2 returns to step 211 of FIG. 18 and the above control processing is repeated. If the first added value ΔVt + ΔVf1 is greater than the threshold value Vth in step 229 , the microcomputer 2 proceeds to step 231 . Even if the second added value ΔVt + ΔVf2 is greater than the threshold value Vth in step 230 , the microcomputer 2 proceeds to step 231 . With this, the microcomputer 2 outputs the crash detection signal to the driver circuit 5 and ends the control processing. The driver circuit 5 , when the collision detection signal is supplied from the microcomputer 2 , outputs the driver signal to the occupant protection device 9 , and thereby the occupant protection device 9 such as an air bag is put into operation. The indoor reference value Gto is the same as in the first embodiment.

Fig. 21 is used for explaining the detection of a collision in the sixth embodiment shown in FIG. 18 to 20. Fig. 21 shows an example of a collision, in which a crash acceleration that is transmitted to the provided on the floor tunnel interior acceleration sensor 8, is weakened. In Fig. 21, reference character (a) denotes the integrated value ΔVf1 (ΔVf2) of the front acceleration sensor 6 ( 7 ), reference character (b) denotes the integrated value ΔVt of the interior acceleration sensor 8 , and reference character (c) denotes the added value Value ΔVt + ΔVf1 (ΔVt + ΔVf2). When a collision occurs, since the front acceleration sensor 6 ( 7 ) is provided in the front portion of the vehicle, the integrated value ΔVf1 (ΔVf2) of the front acceleration sensor 6 ( 7 ) immediately increases as shown in Fig. 21 (a) is shown. Compared with this, since the collision acceleration transmitted to the floor tunnel is weakened due to the absorption of a shock load by a deformation of the vehicle body, the integrated value ΔVt of the interior acceleration sensor 8 rises later than the integrated value ΔVf1 (ΔVf2) of the front acceleration sensor 6 ( 7 ), and exceeds the threshold Vth at time T2 as shown in Fig. 21 (b). The added value DVt + ΔVf1 (ΔVt + ΔVf2) exceeds the threshold value Vth at a time T1 before the time T2, as shown in Fig. 21 (c). Therefore, the microcomputer 2 can provide the crash detection signal to the driver circuit 5 without causing a delay in the crash decision.

In step 227 of FIG. 20, if the absolute value of the acceleration signal Gt of the indoor acceleration sensor 8 is smaller than the indoor reference value Gto, the microcomputer 2 goes to reset processing of steps 232 to 237 , and goes to step 229 after the reset processing. In the reset processing of steps 232 to 237 , the same processing is carried out as in the above-described reset processing of steps 75 to 80 in FIG. 5.

Fig. 22 is 1 is a flow chart for the microcomputer 2 of Fig. According to a seventh embodiment farm. Fig. 22 shows a flowchart in a case where the first and second front acceleration sensors 6 'and 7 ' of Fig. 6 are used, respectively, and this operation is applied to the microcomputer 2 instead of the flowcharts of Figs. 18 and 19 . Terminals M and N of FIG. 22 are connected to terminals with the same designations M and N in FIG. 20. Therefore, FIG. 22 together with FIG. 20 form the flowcharts for the microcomputer 2 .

When control processing is started, the microcomputer 2 of the control unit 1 proceeds to a step 241 after an initialization in a step 240 . An integrated value ΔVf1 of an acceleration signal from the first front acceleration sensor 6 'is supplied to the microcomputer 2 in step 241 , an integrated value ΔVf2 of an acceleration signal is supplied from the first front acceleration sensor 7 ' in step 242 , and then the microcomputer proceeds to step 227 Fig. 20 above. In Fig. 20, as described above, it is decided whether the first added value ΔVt + ΔVf1 of the integrated values ΔVt and ΔVf1 is larger than the threshold value Vth, and it is decided whether the second added value ΔVt + ΔVf2 of the integrated values ΔVt + ΔVf2 integrated values ΔVt and ΔVf2 is greater than the threshold value Vth. If both the first and second added values ΔVt + ΔVf1 and ΔVt + ΔVf2 are smaller than the threshold value Vth, the microcomputer 2 returns to step 241 of FIG. 22. When one of the first and second added values ΔVt + ΔVf1 and ΔVt + ΔVf2 is larger than the threshold value Vth, the microcomputer 2 supplies the driver circuit 5 with the crash detection signal.

In the seventh embodiment described above, since the microcomputer 2 does not have to perform integration or reset processing with respect to the sensor output signals of the first and second front acceleration sensors 6 'and 7 ', respectively, the structure can be simplified and the processing speed can be improved.

FIGS. 23 and 24 show flow diagrams for the microcomputer 2 of FIG. 1 according to an eighth embodiment. The flowcharts of FIGS . 23 and 24 are used in the microcomputer 2 instead of the flowcharts of FIGS . 3-5. Terminals O and P in FIG. 23 are connected to terminals with the same designation O and P in FIG. 24.

When control processing is started, the microcomputer 2 proceeds to step 251 after initialization in step 250 . In step 251 , an acceleration signal Gt of the interior acceleration sensor 8 is supplied to the microcomputer 2 , and the microcomputer decides whether an absolute value of the acceleration signal Gt is greater than a reference value Gto. The reference value Gto is like the interior reference value Gto in the first embodiment. If the absolute value of the acceleration signal Gt is greater than the reference value Gto, the microcomputer 2 proceeds to a step 252 , is supplied with an acceleration signal Gf1 of the first front acceleration sensor 6 , and calculates a first acceleration addition value Gtf1 by adding the acceleration signal Gf1 to the acceleration signal Gt of the interior acceleration sensor 8 . In the following step 253 , an acceleration signal Gf2 of the second front acceleration sensor 7 is supplied to the microcomputer 2 , it calculates a second acceleration addition value Gtf2 by adding the acceleration signal Gf2 to the acceleration signal Gt of the interior acceleration sensor 8 , and it proceeds to a step 254 . The microcomputer 2 calculates an integrated value ΔVtf1 of the first acceleration addition value Gtf1 in step 254 , and calculates an integrated value ΔVtf2 of the second acceleration addition value Gtf2 in the following step 255 . The microcomputer 2 then decides in step 256 whether the integrated value ΔVtf1 of the first acceleration addition value Gtf1 is greater than the threshold value Vth. The threshold Vth is the same as in the sixth embodiment. If the integrated value ΔVtf1 is less than the threshold value Vth, the microcomputer 2 proceeds to a step 257 . In step 257 , the microcomputer 2 decides whether the integrated value ΔVtf2 of the second acceleration addition value Gtf2 is greater than the threshold value Vth. If the integrated value ΔVtf2 is smaller than the threshold value Vth, the microcomputer 2 returns to step 251 and the control processing is repeated. If the integrated value ΔVtf1 of the first acceleration addition value Gtf1 is greater than the threshold value Vth in step 256 , the microcomputer 2 proceeds to a step 258 . If in step 257 the integrated value ΔVtf2 of the second acceleration addition value Gtf2 is greater than the threshold value Vth, the microcomputer 2 also proceeds to step 258 . With this, the microcomputer 2 outputs the crash detection signal to the driver circuit 5 and ends the control processing. The driver circuit 5 , when the collision detector signal is supplied from the microcomputer 2 , outputs the driver signal to the occupant protection device 9 , and thereby the occupant protection device 9 is put into operation.

On the other hand, in step 251, if the absolute value of the acceleration signal Gt of the indoor acceleration sensor 8 is smaller than the front reference value Gfo, the microcomputer 2 proceeds to the flowchart of Fig. 24, and resetting processing of the integrated value ΔVtf1 of the first acceleration addition value Gtf1 in the steps 259 to 264 , and reset processing of the integrated value ΔVtf1 of the second acceleration addition value Gtf2 in steps 265 to 270 , and returns to step 256 of FIG. 23 after the reset processing. In the reset processes of steps 259 to 264 and steps 265 to 270 , the same processing as the above-described reset processing in the first embodiment is performed.

It is therefore decided in step 259 whether the integrated value ΔVtf1 of the first acceleration addition value Gtf1 is "0". The microcomputer 2 goes directly from step 259 to step 265 if the integrated value ΔVtf1 is "0", and proceeds to the following step 260 if the integrated value ΔVtf1 is not "0". In step 260 , a decision is made as to whether an absolute value of the integrated value ΔVtf1 is greater than a reset reference value ΔVto. The reset reference value ΔVto is the same as the interior reset reference value ΔVto in the first embodiment. If the absolute value of the integrated value ΔVtf1 is smaller than the reference value ΔVto, the microcomputer 2 resets the integrated value ΔVtf1 to "0" in step 261 and proceeds to step 265 . If the absolute value of the integrated value ΔVtf1 is larger than the reference value ΔVto, the microcomputer 2 proceeds from step 260 to step 262 and decides whether the integrated value ΔVtf1 is larger than "0". If the integrated value ΔVtf1 is greater than "0", the subtraction value "a" is subtracted from the integrated value ΔVtf1 in step 263 . If the integrated value ΔVtf1 is not greater than "0", the subtraction value "a" is added to the integrated value ΔVtf1 in step 264 . The microcomputer 2 then proceeds to step 265 .

In step 265 , it is decided whether the integrated ΔVtf2 of the second acceleration addition value Gtf2 is "0". The microcomputer 2 proceeds from step 265 to step 256 of Fig. 23 when the integrated value ΔVtf2 is "0", and proceeds to the following step 266 when the integrated value ΔVtf2 is not "0". In step 266 , a decision is made as to whether an absolute value of the integrated value ΔVtf2 is larger than the reset reference value ΔVto. If the absolute value of the integrated value ΔVtf2 is smaller than the reference value ΔVto, the microcomputer 2 resets the integrated value ΔVtf2 to "0" in step 267 and proceeds to step 256 of FIG. 23. If the absolute value of the integrated value ΔVtf2 is larger than the reference value ΔVto, the microcomputer 2 proceeds from step 266 to step 268 and decides whether the integrated value ΔVtf2 is larger than "0". If the integrated value ΔVtf2 is greater than "0", the subtraction value "a" is subtracted from the integrated value ΔVtf2 in step 269 . If the integrated value ΔVtf2 is not greater than "0", the subtraction value "a" is added to the integrated value ΔVtf2 in step 270 . The microcomputer 2 then proceeds to step 256 of FIG. 23.

In the eighth embodiment, the first acceleration addition value Gtf1 is calculated by adding the acceleration signal Gf1 of the first front acceleration sensor 6 to the acceleration signal Gt of the interior acceleration sensor 8 , and the second acceleration addition value Gtf2 is calculated by the acceleration signal Gf2 of the second front acceleration sensor 7 is added to the acceleration signal Gt of the interior acceleration sensor 8 . If either the integrated value ΔVtf1 of the first acceleration addition value Gtf1 or the integrated value ΔVtf2 of the second acceleration addition value Gtf2 exceeds the threshold value Vth, the occupant protection device 9 is started. As a result, even in the case of a collision in which a collision acceleration transmitted to the interior acceleration sensor 8 is weakened, the sixth embodiment shown in Figs. 18 and 20 can ensure that the control unit can operate the occupant protection device 9 exactly without to cause a delay in the collision decision.

FIGS. 25 and 26 are flowcharts to the microcomputer 2 of FIG. 1 according to a ninth embodiment. The flowcharts of FIGS . 25 and 26 are used in the microcomputer 2 instead of the flowcharts of FIGS . 18 and 19. A connector M of Fig. 25 is connected to a connector with the same designation M of Fig. 20, and connectors N and Q of Fig. 26 are connected to connectors with the same designation N and Q of Fig. 20 and Fig. 25. Therefore, FIGS. 25 and 26 together with FIG. 20 form the flowcharts for the microcomputer 2 .

At the beginning of the control processing, the microcomputer 2 of the control unit 1 proceeds to a step 281 after an initialization in a step 280 . In step 281 , an acceleration signal Gf1 of the first front acceleration sensor 6 is supplied to the microcomputer 2 , and the microcomputer decides whether an absolute value of the acceleration signal Gf1 is greater than the front reference value Gfo. The front reference value Gfo is as described in the first embodiment. If the absolute value of the acceleration signal Gf1 is larger than the reference value Gfo, the microcomputer 2 proceeds to a step 282 and decides whether the acceleration signal Gf1 is larger than a predetermined value Gth. The predetermined value Gth is a threshold value for subtracting a crash acceleration signal to be integrated from a crash acceleration signal that comes from the front acceleration sensor 6 (FIG. 7 ) at the time of a vehicle crash. The predetermined value Gth is set to a value larger than the front reference value Gfo. The predetermined value Gth is set on the basis of tests, on the basis of a collision acceleration that occurs in a collision in which, for example, starting of the occupant protection device 9 is not required. If the acceleration signal Gf1 is greater than the value Gth, the microcomputer 2 proceeds from step 282 to a step 283 , calculates an acceleration component Gf1-Gth above the predetermined value Gth by subtracting the predetermined value Gth from the acceleration signal Gf1, calculates an integrated one Value ΔVf1 of the acceleration component Gf1-Gth, and proceeds to a step 290 in FIG. 26. If the acceleration signal Gf1 is less than the value Gth, the microcomputer 2 proceeds directly to step 290 of FIG. 26 without going through step 283 .

On the other hand, in step 281, if the absolute value of the acceleration signal Gf1 is less than the front reference value Gfo, the microcomputer 2 goes to reset processing of steps 284 to 289 , and after the reset processing goes to step 290 of Fig. 26. In the reset processing of steps 284 to 289 , the same processing is performed as the above-described reset processing of steps 56 to 61 in FIG. 3.

In step 290 of FIG. 26, an acceleration signal Gf2 of the second front acceleration sensor 7 is supplied to the microcomputer 2 , and the microcomputer decides whether an absolute value of the acceleration signal Gf2 is greater than the front reference value Gfo. If the absolute value of the acceleration signal Gf2 is larger than the reference value Gfo, the microcomputer 2 proceeds to step 291 and decides whether the acceleration signal Gf2 is larger than the predetermined value Gth. If the acceleration signal Gf2 is larger than the value Gth, the microcomputer 2 proceeds to a step 292 , calculates an acceleration component Gf2-Gth above the predetermined value Gth by subtracting the predetermined value Gth from the acceleration signal Gf2, calculates an integrated value ΔVf2 of the acceleration component Gf2-Gth, and proceeds to step 227 of FIG. 20. If the acceleration signal Gf2 is less than the value Gth, the microcomputer 2 proceeds directly to step 227 of FIG. 20 without going through step 292 .

On the other hand, in step 290, if the absolute value of the acceleration signal Gf2 is smaller than the front reference value Gfo, the microcomputer 2 goes to reset processing of steps 293 to 298 , and goes to step 227 of Fig. 20 after the reset processing. In the reset processing of steps 293 to 298 , the same processing is carried out as in the above-described reset processing of steps 66 to 71 in FIG. 4.

Fig. 27 is used to explain the integration processing of the acceleration signal Gf1 (Gf2) of the front acceleration sensor 6 ( 7 ) in the ninth embodiment shown in Figs. 25, 26 and 20. In Fig. 27, reference numeral (a) denotes the acceleration signal Gf1 (Gf2 ) of the front acceleration sensor 6 ( 7 ) at the time of a weak collision, and a reference character (b) denotes this signal at the time of a strong collision. In the ninth embodiment, the acceleration component Gf1-Gth (Gf2-Gth), which is shown hatched, is integrated in the acceleration signal Gf1 (Gf2) above the predetermined value Gth. An acceleration component below the predetermined value Gth is not integrated. Therefore, a ratio between an integrated value in a small collision and an integrated value in a strong collision becomes large compared to a case in which the entire acceleration signal Gf1 (Gf2) is integrated. Therefore, the difference in the size of the built-in values becomes small and large. Clash more clearly. Therefore, when the integrated value of the indoor acceleration sensor 8 and the integrated value of the front acceleration sensor 6 ( 7 ) are added as described above, the added value in a strong collision becomes larger than the added value in a weak collision. Therefore, it is easy to distinguish between a collision that requires the occupant protection device 9 to be started and a collision that does not require it.

In FIG. 20, as mentioned above, a first added value ΔVt + ΔVf1 is calculated by adding the integrated value ΔVf1 of the acceleration component Gf1-Gth of the first front acceleration sensor 6 to the integrated value ΔVt of the interior acceleration sensor 8 , and a decision is made whether the first added value ΔVt + ΔVf1 is greater than the threshold value Vth. Furthermore, a second added value ΔVt + ΔVf2 is calculated by adding the integrated value ΔVf2 of the acceleration component Gf2-Gth of the second front acceleration sensor 7 to the integrated value ΔVt of the interior acceleration sensor 8 , and a decision is made as to whether the second added value ΔVt + ΔVf2 is greater is than the threshold Vth. If the first and second added values .DELTA.Vt + .DELTA.Vf1 and .DELTA.Vt + .DELTA.Vf2 are smaller than the threshold value Vth, the microcomputer 2 returns to step 281 of FIG. 25. If either the first or the second added value ΔVt + ΔVf1 or ΔVt + ΔVf2 is larger than the threshold value Vth, the microcomputer 2 outputs the crash detector signal to the driver circuit 5 .

In the ninth embodiment described above, the acceleration component Gf1-Gth above the predetermined value Gth is subtracted from the acceleration signal Gf1 of the first front acceleration sensor 6 , and the first added value ΔVt + ΔVf1 is calculated by the integrated value ΔVf1 of the acceleration component Gf1-Gth is added to the integrated value ΔVt of the interior acceleration sensor 8 . Furthermore, the acceleration component Gf2-Gth above the predetermined value Gth is subtracted from the acceleration signal Gf2 of the second front acceleration sensor 7 , and the second added value ΔVt + ΔVf2 is calculated in that the integrated value ΔVf2 of the acceleration component Gf2-Gth to the integrated value ΔVt of Interior acceleration sensor 8 is added. If either the first or the second added value ΔVt + ΔVf1 or ΔVt + ΔVf2 exceeds the threshold value Vth, the occupant protection device 9 is put into operation. Therefore, as in the sixth embodiment shown in FIGS. 18 to 20, even in the event of a collision in which a collision acceleration that is transmitted to the interior acceleration sensor 8 is weakened, the control unit 1 can accurately control the occupant protection device 9 in Put into operation without causing a delay in the collision decision.

Although the sixth, seventh, eighth and ninth Embodiment two front acceleration sensors used, however, the number of front Acceleration sensors, as already mentioned above was mentioned to be one or greater than two.

The foregoing should make it clear be that a new and improved controller for a Occupant protection device was found. Of course the described embodiments are only examples understand, and are not intended to limit the scope of the invention restrict. The overall scope of the invention results from the entirety of the present application documents and should be encompassed by the appended claims.

Claims (48)

1. Control device of an occupant protection device, which has an interior acceleration sensor which is provided in an interior of a vehicle, for detecting an acceleration of a vehicle and for outputting a corresponding acceleration signal, the following being provided:
at least one front acceleration sensor, which is arranged in a front part of the vehicle, for detecting the acceleration of the vehicle and for outputting a corresponding acceleration signal, or an integrated value of the acceleration signal as a sensor output signal; and
a control unit, which is connected to the interior acceleration sensor and the front acceleration sensor, for inputting the acceleration signal of the interior acceleration sensor and the sensor output signal of the front acceleration sensor,
wherein the control unit puts the occupant protection device into operation when an integrated value of the acceleration signal of the interior acceleration sensor exceeds a predetermined threshold value,
the control unit detects whether a collision occurs in the vehicle requiring activation of the occupant protection device based on the sensor output signal of the front acceleration sensor, and increases the integrated value of the interior acceleration sensor when the collision based on the sensor output signal of the front Acceleration sensor is detected. 2. Control device according to claim 1, characterized in that it has a first and a second front acceleration sensor, wherein
the control unit detects whether the vehicle is colliding based on each sensor output of the first and second acceleration sensors;
the control unit adds a first addition value to the integrated value of the acceleration signal of the indoor acceleration sensor when the collision is detected either based on the detection based on the first front acceleration sensor or based on the detection based on the second front acceleration sensor; and
the control unit adds a second addition value, which is larger than the first addition value, to the integrated value of the acceleration signal of the interior acceleration sensor when the collision by both the detection based on the first front acceleration sensor and by the detection based on the second front Acceleration sensor is detected. 3. Control device according to claim 2, characterized in that
the control unit detects a first collision time indicating a time of the collision that is detected based on the sensor output signal of the first front acceleration sensor and a second collision time indicating a time of the collision based on the sensor output signal of the second front acceleration sensor is detected; and
the control unit decides whether a time difference between the first and second collision times is less than a predetermined time value if the collision is detected both by the detection based on the first front acceleration sensor and by the detection based on the second front acceleration sensor, and a third addition value, which is larger than the second addition value, is added to the integrated value of the acceleration signal of the interior acceleration sensor if the time difference is less than the predetermined time value. 4. Control device according to claim 1, characterized in that
the front acceleration sensor outputs the acceleration signal;
the control unit has a front reference value for deciding whether the acceleration signal of the front acceleration sensor is integrated;
the control unit integrates the acceleration signal of the front acceleration sensor when the acceleration signal of the front acceleration sensor is larger than the front reference value, and detects the collision based on a comparison between an integrated value of the acceleration signal and a predetermined front threshold value; and
the control unit, when the acceleration signal of the front acceleration sensor is smaller than the front reference value, gradually processes the integrated value of the acceleration signal of the front acceleration sensor toward a reset direction. 5. Control device according to claim 2 or 3, characterized in that the first and the second front accelerometer nearby a right and left section of a radiator one Vehicle front are provided. 6. Control device of an occupant protection device which has an interior acceleration sensor provided in an interior of a vehicle for detecting an acceleration of the vehicle and for outputting a corresponding acceleration signal, the following being provided:
at least one front acceleration sensor, which is arranged in a front part of the vehicle, for detecting the acceleration of the vehicle and for outputting a corresponding acceleration signal or an integrated value of the acceleration signal as a sensor output signal; and
a control unit, which is connected to the interior acceleration sensor and the front acceleration sensor, for inputting the acceleration signal of the interior acceleration sensor and the sensor output signal of the front acceleration sensor,
the control unit calculating an added value by adding the integrated value of the acceleration signal of the front acceleration sensor to an integrated value of the acceleration signal of the interior acceleration sensor, and actuating the occupant protection device when the added value exceeds a predetermined threshold value. 7. Control device according to claim 6, characterized by a plurality of front acceleration sensors, wherein:
the control unit calculates each added value by adding each integrated value of acceleration signals of the front acceleration sensors to the integrated value of the acceleration signal of the interior acceleration sensor, and starts the occupant protection device when one of the added values exceeds the predetermined threshold value. 8. Control device according to claim 6, characterized in that
the front acceleration sensor outputs the acceleration signal;
the control unit has a front reference value to decide whether the acceleration signal of the front acceleration sensor is integrated;
the control unit integrates the acceleration signal of the front acceleration sensor when the acceleration signal of the front acceleration sensor is greater than the front reference value; and
when the acceleration signal of the front acceleration sensor is smaller than the front reference value, the control unit gradually processes the integrated value of the acceleration signal of the front acceleration sensor towards a reset direction. 9. Control device for an occupant protection device, which is provided with an interior acceleration sensor provided in an interior of a vehicle, for detecting an acceleration of the vehicle and for outputting a corresponding acceleration signal, the following being provided:
at least one front acceleration sensor, which is provided in a front part of the vehicle, for detecting the acceleration of the vehicle and for outputting a corresponding acceleration signal; and
a control unit, which is connected to the interior acceleration sensor and the front acceleration sensor, for inputting the acceleration signals of the interior acceleration sensor and the front acceleration sensor,
wherein the control unit calculates an acceleration addition value by adding the acceleration signal of the front acceleration sensor to the acceleration signal of the interior acceleration sensor, and calculates an integrated value of the acceleration addition value,
and the control unit starts the occupant protection device when the integrated value of the acceleration addition value exceeds a predetermined threshold value. 10. Control device according to claim 9, characterized by a plurality of front acceleration sensors, wherein
the control unit in each case calculates acceleration addition values in that each acceleration signal of the front acceleration sensors is added to the acceleration signal of the interior acceleration sensor, in each case calculates integrated values of the acceleration addition values, and
the occupant protection device starts when one of the integrated values exceeds the predetermined threshold. 11. Control device according to claim 9, characterized in that
the control unit has a reference value to decide whether the acceleration signal of the interior acceleration sensor is integrated;
the control unit calculates the acceleration addition value and the integrated value of the acceleration addition value when the acceleration signal of the interior acceleration sensor is larger than the reference value; and
the control unit, when the acceleration signal of the interior acceleration sensor is smaller than the reference value, gradually processes the integrated value of the acceleration addition value toward a reset direction. 12. Control device of an occupant protection device, which has an interior acceleration sensor arranged in the interior of a vehicle, for detecting an acceleration of the vehicle and for outputting a corresponding acceleration signal, the following being provided:
at least one front acceleration sensor, which is arranged in a front part of the vehicle, for detecting the acceleration of the vehicle and for outputting a corresponding acceleration signal; and
a control unit, which is connected to the interior acceleration sensor and the front acceleration sensor, for inputting the acceleration signals of the interior acceleration sensor and the front acceleration sensor,
wherein the control unit subtracts an acceleration component above a predetermined acceleration value from the acceleration signal of the front acceleration sensor, and calculates an integrated value of the acceleration component,
and the control unit calculates an added value by adding the integrated value of the acceleration portion to an integrated value of the acceleration signal of the interior acceleration sensor, and operates the occupant protection device when the added value exceeds a predetermined threshold value. 13. Control unit according to claim 12, characterized in that a plurality of front acceleration sensors are provided, wherein:
the control unit in each case subtracts acceleration components above the predetermined acceleration value from acceleration signals of the front acceleration sensors, in each case calculates integrated values of the acceleration components, in each case adds values by adding each integrated value of the acceleration components to the integrated value of the acceleration signal of the interior acceleration sensor, and calculates the occupant protection device in Gear sets when one of the added values exceeds the predetermined threshold. 14. Control device according to claim 12, characterized in that
the control unit has a front reference value to decide whether the acceleration signal of the front acceleration sensor should be integrated;
the control unit subtracts the acceleration component in order to integrate it when the acceleration signal of the front acceleration sensor is greater than the front reference value; and
the control unit, when the acceleration signal of the front acceleration sensor is smaller than the front reference value, gradually processes the integrated value of the acceleration signal of the front acceleration sensor toward a reset direction. 15. Control device according to claim 1, 6, 9 or 12, characterized in that the front Accelerometer near a radiator in one provided central portion of a vehicle front is. 16. Control device according to claim 7, 10 or 13,  characterized in that they have a first and a second front acceleration sensor has, the first and the second front Acceleration sensor near a right or left section of a radiator one Vehicle front is arranged. 17. Control device according to claim 1, 6, 9 or 12, characterized in that the front acceleration sensor comprises:
a piezoelectric element for detecting the acceleration;
an amplifier circuit for inputting output voltages at both ends of the piezoelectric element and outputting the acceleration signal by differential amplification of the output voltages of the piezoelectric element;
a bias resistance circuit provided on an input side of the amplifier circuit;
a capacitor connected in parallel with the piezoelectric element to lower a lower cut-off frequency without increasing resistance values of the bias resistance circuit;
a temperature compensation device for adjusting a gain of the amplifier circuit so that an output temperature characteristic of the piezoelectric element is compensated; and
a reference voltage circuit for providing a reference potential for the amplifier circuit and the bias resistance circuit. 18. Control device according to claim 17, characterized in that the Capacitance of the capacitor is set so that Resistors of the bias resistor circuit have values such that use in a normal atmosphere can be made, and the lower Cutoff frequency has a low value at which simply detects speed changes can be. 19. Control device according to claim 17, characterized in that
the amplifier circuit comprises a first non-inverting amplifier circuit for non-inverting amplification of an output voltage of the piezoelectric element, a second non-inverting amplifier circuit for non-inverting amplification of the other output voltage of the piezoelectric element, and a differential amplifier circuit for differential amplification of output signals of the first and the second non-inverting amplifier circuit; and
the temperature compensation device is a single temperature compensation element for setting the gains of the first and the second non-inverting amplifier circuit. 20. Control device according to claim 19, characterized in that
the first non-inverting amplifier circuit comprises a first operational amplifier, one input terminal of the first operational amplifier being connected to one end of the piezoelectric element and the other input terminal of the first operational amplifier being connected to an output terminal of the first operational amplifier via a first resistor;
the second non-inverting amplifier circuit comprises a second operational amplifier, one input terminal of the second operational amplifier being connected to the other end of the piezoelectric element, and the other input terminal of the second operational amplifier being connected to an output terminal of the second operational amplifier via a second resistor; and
the temperature compensation element is inserted between the other input terminal of the first operational amplifier and the other input terminal of the second operational amplifier, and the gain of the first and second operational amplifiers decreases as the temperature rises and increases as the temperature falls. 21. Control device according to claim 19, characterized in that the Reinforcements of the first and the second non- inverting amplifier circuit are set so  that a drop in the output voltages of the piezoelectric element due to the parallel connection of the capacitor to the piezoelectric element can be compensated. 22. Control device according to claim 19, characterized in that
the differential amplifier circuit comprises an operational amplifier, one input terminal of the operational amplifier receiving the output signal of the second non-inverting amplifier circuit and the reference potential of the reference voltage circuit, and the other input terminal of the operational amplifier receiving the output signal of the first non-inverting amplifier circuit; and
the reference voltage circuit has a reference voltage buffer amplifier for matching the output impedances of the first and the second non-inverting amplifier circuit, and supplies the reference potential to at least the differential amplifier circuit via the reference voltage buffer amplifier. 23. Control device according to claim 17, characterized in that
the front acceleration sensor has a sensor voltage supply line, to which a constant voltage is supplied from the outside, an output terminal of the amplifier circuit of the front acceleration sensor is grounded via an output resistor, and the acceleration signal of the front acceleration sensor is output as current changes in the sensor voltage supply line; and
the control unit has a unit voltage supply line for supplying the constant voltage to the sensor voltage supply line via a transmission cable, and a receiving circuit for receiving the acceleration signal of the front acceleration sensor by detecting the current changes in the unit voltage supply line. 24. Control device according to claim 23, characterized in that the receiving circuit comprises:
a current mirror circuit interposed between the unit power supply line and the transmission cable for outputting an output current in accordance with the current changes representing the acceleration signal of the front acceleration sensor; and
a detector resistor, which is inserted between an output side of the current mirror circuit and ground, for outputting a voltage signal which corresponds to the output current of the current mirror circuit. 25. Control device according to claim 1 or 6, characterized in that the front acceleration sensor has:
a piezoelectric element for detecting the acceleration;
an amplifier circuit for inputting output voltages of both ends of the piezoelectric element, for differential amplification and for integrating the output voltages of the piezoelectric element, and for outputting the integrated value of the acceleration signal as the sensor output signal;
a bias resistance circuit provided on an input side of the amplifier circuit;
a capacitor connected in parallel with the piezoelectric element to lower a lower cut-off frequency without increasing resistance values of the bias resistance circuit;
a temperature compensation device for adjusting a gain of the amplifier circuit in such a manner that the output temperature characteristic of the piezoelectric element is compensated; and
a reference voltage circuit for providing a reference potential for the amplifier circuit and the bias resistance circuit. 26. Control device according to claim 25, characterized in that the Capacitance of the capacitor is set so that  Resistors of the bias resistor circuit values have used in a normal atmosphere and so that the lower cutoff frequency has a low value at which Changes in speed can be easily detected can. 27. Control device according to claim 25, characterized in that
the amplifier circuit comprises a first non-inverting amplifier circuit for non-inverting amplification of an output voltage of the piezoelectric element, a second non-inverting amplifier circuit for non-inverting amplification of the other output voltage of the piezoelectric element, and a differential amplifier circuit for differential amplification of output signals of the first and the second non-inverting amplifier circuit, wherein the first and the second non-inverting amplifier circuit and / or the differential amplifier circuit have an integration function; and
the temperature compensation device is a single temperature compensation element for adjusting the gains of the first and the second non-inverting amplifier circuit. 28. Control device according to claim 27, characterized in that
the first non-inverting amplifier circuit has a first operational amplifier, an input terminal of the first operational amplifier being connected to one end of the piezoelectric element, and the other input terminal of the first operational amplifier being connected to an output terminal of the first operational amplifier via a parallel circuit comprising a first resistor and a first capacitor connected is;
the second non-inverting amplifier circuit has a second operational amplifier, one input terminal of the second operational amplifier being connected to the other end of the piezoelectric element, and the other input terminal of the second operational amplifier being connected to an output terminal of the second operational amplifier via a parallel connection of a second resistor and a second capacitor connected is; and
the temperature compensation element is inserted between the other input terminal of the first operational amplifier and the other input terminal of the second operational amplifier, and lowers the gains of the first and second operational amplifiers as the temperature rises and increases these gains as the temperature decreases. 29. Control device according to claim 27, characterized in that the Differential amplifier circuit a third Has operational amplifier, with an input terminal of the third operational amplifier with one  Output terminal of the second non-inverting Amplifier circuit via a third resistor connected, and continues with the Reference voltage circuit via a parallel circuit a fourth resistor and a third capacitor is connected, and the other input terminal of the third Operational amplifier with an output terminal of the first non-inverting amplifier circuit a fifth resistor is connected, and continues with an output terminal of the third Operational amplifier via a parallel connection a sixth resistor and a fourth capacitor connected is. 30. Control device according to claim 27, characterized in that the Reinforcements of the first and the second non- inverting amplifier circuit are set so that a drop in the output voltages of the piezoelectric element due to the parallel connection of the capacitor to the piezoelectric element can be compensated. 31. Control device according to claim 27, characterized in that
the differential amplifier circuit comprises an operational amplifier, one input terminal of the operational amplifier receiving the output signal of the second non-inverting amplifier circuit and the reference potential of the reference voltage circuit, and the other input terminal of the operational amplifier receiving the output signal of the first non-inverting amplifier circuit; and
the reference voltage circuit has a reference voltage buffer amplifier for matching the output impedances of the first and second non-inverting amplifier circuits, and supplies the reference potential to at least the differential amplifier circuit via the reference voltage buffer amplifier. 32. Control device according to claim 25, characterized in that
the front acceleration sensor has a sensor voltage supply line to which a constant voltage is supplied from the outside, an output terminal of the amplifier circuit of the front acceleration sensor being grounded via an output resistor, and the integrated value of the acceleration signal being output by the front acceleration sensor as current changes in the sensor voltage supply line ; and
the control unit has a unit voltage supply line for supplying the constant voltage to the sensor voltage supply line via a transmission cable, and a receiving circuit for receiving the integrated value of the acceleration signal from the front acceleration sensor by detecting the current changes in the unit voltage supply line. 33. Control device according to claim 32, characterized in that the receiving circuit comprises:
a current mirror circuit interposed between the unit power supply line and the transmission cable for outputting an output current in accordance with the current changes representing the integrated value of the acceleration signal of the front acceleration sensor; and
a detector resistor inserted between an output side of the current mirror circuit and ground for outputting a voltage signal corresponding to the output current of the current mirror circuit. 34. Control device of an occupant protection device, which has an interior acceleration sensor arranged in an interior of a vehicle, for detecting an acceleration of the vehicle and for outputting a corresponding acceleration signal, the following being provided:
first and second front acceleration sensors arranged in a front portion of the vehicle, both the first and second front acceleration sensors detecting the acceleration of the vehicle and outputting a corresponding acceleration signal or an integrated value of the acceleration signal as a sensor output signal; and
a control unit, which is connected to the interior acceleration sensor, with the first front acceleration sensor and the second front acceleration sensor, for inputting the acceleration signal of the interior acceleration sensor and the sensor output signals of the first and the second front acceleration sensor,
wherein the control unit puts the occupant protection device into operation when an integrated value of the acceleration signal of the interior acceleration sensor exceeds a predetermined threshold value,
the control unit detects whether a collision occurs in the vehicle, which makes it necessary to start the occupant protection device, based on each sensor output signal of the first and second acceleration sensors,
the control unit detects a first collision time indicating a time of the collision that is detected based on the sensor output signal of the first front acceleration sensor and a second collision time indicating a time of the collision based on the sensor output signal of the second front acceleration sensor is detected
and the control unit adds a predetermined addition value to the integrated value of the acceleration signal of the indoor acceleration sensor when a time difference between the first collision time and the second collision time is less than a predetermined time value. 35. Control device according to claim 2, 3 or 34, characterized in that
the first and second front acceleration sensors output the respective acceleration signal;
the control unit has a front reference value to decide whether each acceleration signal of the first and second front acceleration sensors should be integrated;
the control unit integrates each acceleration signal of the first and second front acceleration sensors when each acceleration signal of the first and second front acceleration sensors is greater than the front reference value, and the collision based on a comparison between each integrated value of the first and second acceleration sensors and one predetermined front threshold is detected; and
when each acceleration signal of the first and second front acceleration sensors is less than the front reference value, the control unit gradually processes each integrated value of the first and second front acceleration sensors toward a reset direction. 36. Control device according to claim 34, characterized in that the first and the second front accelerometer nearby a right and left section of a radiator one Vehicle front is arranged. 37. Control device according to claim 34, characterized in that each of the first and second front acceleration sensors comprises:
a piezoelectric element for detecting the acceleration;
an amplifier circuit for inputting output voltages at both ends of the piezoelectric element and outputting the acceleration signal by differential amplification of the output voltages of the piezoelectric element;
a bias resistance circuit provided on an input side of the amplifier circuit;
a capacitor connected in parallel with the piezoelectric element to lower a lower cut-off frequency without increasing resistance values of the bias resistance circuit;
a temperature compensation device for adjusting a gain of the amplifier circuit in such a manner that an output temperature characteristic of the piezoelectric element is compensated;
and a reference voltage circuit for providing a reference potential for the amplifier circuit and the bias resistance circuit. 38. Control device according to claim 37, characterized in that
the amplifier circuit comprises a first non-inverting amplifier circuit for non-inverting amplifying an output voltage of the piezoelectric element, a second non-inverting amplifier circuit for non-inverting amplifying the other output voltage of the piezoelectric element, and a differential amplifier circuit for differential amplifying output signals of the first and the second non-inverting amplifier circuit; and
the temperature compensation device is a single temperature compensation element for adjusting the gains of the first and the second non-inverting amplifier circuit. 39. Control device according to claim 38, characterized in that
the first non-inverting amplifier circuit comprises a first operational amplifier, one input terminal of the first operational amplifier being connected to one end of the piezoelectric element and the other input terminal of the first operational amplifier being connected to an output terminal of the first operational amplifier via a first resistor;
the second non-inverting amplifier circuit comprises a second operational amplifier, one input terminal of the second operational amplifier being connected to the other end of the piezoelectric element, and the other input terminal of the second operational amplifier being connected to an output terminal of the second operational amplifier via a second resistor; and
the temperature compensation element is inserted between the other input terminal of the first operational amplifier and the other input terminal of the second operational amplifier, and the gain of the first and the second operational amplifier is reduced as the temperature rises and these gains are increased as the temperature falls. 40. Control device according to claim 34, characterized in that each of the first and second front acceleration sensors has:
a piezoelectric element for detecting the acceleration;
an amplifier circuit for inputting output voltages of both ends of the piezoelectric element, for differential amplification and for integrating the output voltages of the piezoelectric element, and for outputting the integrated value of the acceleration signal as a sensor output signal;
a bias resistance circuit provided on an input side of the amplifier circuit;
a capacitor connected in parallel with the piezoelectric element to lower a lower cut-off frequency without increasing resistance values of the bias resistance circuit;
a temperature compensation device for adjusting a gain of the amplifier circuit in such a manner that an output temperature characteristic of the piezoelectric element is compensated; and
a reference voltage circuit for providing a reference potential for the amplifier circuit and the bias resistance circuit. 41. Control device according to claim 37 or 40, characterized in that the Capacitance of the capacitor is set so that Resistors of the bias resistor circuit values have used in a normal atmosphere and the lower cutoff frequency is one has a low value at which Changes in speed can be easily detected can. 42. Control device according to claim 40, characterized in that
the amplifier circuit comprises a first non-inverting amplifier circuit for non-inverting amplifying an output voltage of the piezoelectric element, a second non-inverting amplifier circuit for non-inverting amplifying the other output voltage of the piezoelectric element, and a differential amplifier circuit for differential amplifying output signals of the first and the second non-inverting amplifier circuit, wherein the first and the second non-inverting amplifier circuit and / or the differential amplifier circuit have an integration function; and
the temperature compensation device is a single temperature compensation element for adjusting the gains of the first and the second non-inverting amplifier circuit. 43. Control device according to claim 42, characterized in that
the first non-inverting amplifier circuit has a first operational amplifier, an input terminal of the first operational amplifier being connected to one end of the piezoelectric element, and the other input terminal of the first operational amplifier being connected to an output terminal of the first operational amplifier via a parallel circuit comprising a first resistor and a first capacitor connected is;
the second non-inverting amplifier circuit has a second operational amplifier, one input terminal of the second operational amplifier being connected to the other end of the piezoelectric element, and the other input terminal of the second operational amplifier being connected to an output terminal of the second operational amplifier via a parallel circuit comprising a second resistor and a second Capacitor is connected; and
the temperature compensation element is inserted between the other input terminal of the first operational amplifier and the other input terminal of the second operational amplifier, and lowers the gains of the first and second operational amplifiers as the temperature rises and increases these gains as the temperature decreases. 44. Control device according to claim 42, characterized in that the Differential amplifier circuit a third Has operational amplifier, with an input terminal of the third operational amplifier with one Output terminal of the second non-inverting Amplifier circuit via a third resistor is connected, and to the reference voltage circuit via a parallel connection of a fourth resistor and a third capacitor is connected, and the other Input terminal of the third operational amplifier with an output terminal of the first non-inverting Amplifier circuit through a fifth resistor is connected, and to an output terminal of the third Operational amplifier via a parallel connection  a sixth resistor and a fourth capacitor connected is. 45. Control device according to claim 38 or 42, characterized in that the Reinforcement of the first and second non- inverting amplifier circuit is set so that a drop in the output voltage of the piezoelectric element due to the parallel connection of the capacitor to the piezoelectric element can be compensated. 46. Control device according to claim 38 or 42, characterized in that
the differential amplifier circuit comprises an operational amplifier, one input terminal of the operational amplifier receiving the output signal of the second non-inverting amplifier circuit and the reference potential of the reference voltage circuit, and the other input terminal of the operational amplifier receiving the output signal of the first non-inverting amplifier circuit; and
the reference voltage circuit has a reference voltage buffer amplifier for matching to output impedances of the first and second non-inverting amplifier circuit, and supplies the reference potential at least to the differential amplifier circuit via the reference voltage buffer amplifier. 47. Control device according to claim 37 or 40, characterized in that
each front acceleration sensor has a sensor voltage supply line, to which a constant voltage is supplied from the outside, an output terminal of the amplifier circuit of each front acceleration sensor being connected to ground via an output resistor, and the acceleration signal or the integrated value of the acceleration signal of each front acceleration sensor being output as current changes in the sensor voltage supply line becomes; and
the control unit has unit voltage supply lines for supplying the constant voltages to the sensor voltage supply line of each front acceleration sensor via transmission cables, and a first and a second receiving circuit for receiving the acceleration signal or the integrated value of the acceleration signal of each front acceleration sensor by detecting the respective current changes in the respective unit voltage supply line. 48. Control device according to claim 47, characterized in that each first and second receiving circuit has:
a current mirror circuit interposed between the unit power supply line and the transmission cable for outputting an output current in accordance with the current changes representing the acceleration signal of the front acceleration sensor; and
a detector resistor interposed between an output side of the current mirror circuit and ground for outputting a voltage signal corresponding to the output current of the current mirror circuits.